List of The Secret Saturdays episodes

When the Saturday family travels to Tokyo, Japan to deal with an attacking Hibagon, they discover that it is actually a professor named Talu Mizuki. The scientist became trapped in the cryptid's body after using a mind-transfer device he invented to escape the Japanese crimelord and philanthropist Shoji Fuzen. A fire that burned his laboratory caused Talu to lose his human body in the process. Now bitter and wanting revenge, the Saturdays have to keep Mizuki from killing the crimelord. In the end, after getting Fuzen put in jail, they give Mizuki the technology needed for him to continue his research.

Doc and Drew decide to go out for their anniversary, leaving Zak, Fiskerton, Komodo and Zon to watch the house. After tricking Dr. Beeman (their babysitter and another Secret Scientist) into thinking he's sighted a UFO, they get the house to themselves and decide to have some fun. However, a cryptid-eating criminal named Pietro "Piecemeal" Maltese invades the Saturdays HQ. While they are able to fight him off for a while, ignorant of his true intentions, they discover that he plans to eat Fiskerton. Zak is able to save the gorilla-cat by using his mother's Tibetan Fire Sword, but (unbeknown to the family) Piecemeal manages to survive the attack and escape.

After the Saturdays track down the Popobawa in Pemba, Tanzania, they receive a distress call from a Secret Scientist claiming that the lost city of Kumari Kandam has resurfaced. Once they get there, they find that V.V. Argost has become the new king of the city. Doc and Drew are captured by his soldiers, while Zak and the cryptids escape to safety in the airship. They return to save Doc and Drew when they meet Ulraj (a prince whose father was killed by Argost's plan) who is the rightful heir to the city. Zak helps the boy reclaim his position as king, with the help of Doc. Unfortunately, despite saving the city and the Indian subcontinent, Drew is injured and Argost and Munya escape with another clue to locating Kur.

When the Saturdays rescue an aircraft under attack by a swarm of atmospheric jellyfish, they discover that it's Agent Epsilon and his son, Francis, who appeared to do nothing but play a video game. The Jellyfish turn on their airship, injuring Epsilon in the ensuing battle. Zak soon discovers that Francis is the one responsible for provoking the Jellyfish, as his "game" is actually a prototype control device that's driving them crazy. Francis forces Zak into capturing one of the Jellyfish for study, but Zak is able to sneak the control device into the container with it, forcing Francis to abandon both once he discovers the trick.

When water supplies in the Middle East are inexplicably turning into salt, the Secret Scientists send Drew and Zak Saturday into the area to investigate. A thief named Wadi reveals that she's the cause, having released Eterno, a giant man made of salt who has an unquenchable thirst and a death wish. When Drew and some local villagers refuse to lead him to the Methuselah Tree, Eterno turns them into salt statues in a state of suspended animation. Zak and Wadi venture to the plant to gain the sap Eterno requires to end his suffering. But Wadi steals a flower from the tree, which sends two Centiscarabs after her. Eterno later steals the flower and uses all the sap, which destroys him. The scientists synthesize more sap from the remains, and return everything back to normal.

When Zak touches the mystic Smoke Mirror of Tezcatlipoca, it unleashes what Zak christens the Monday family, evil doppelgangers of the Saturdays with their own unique powers. The duplicates attempt to trap the Saturday family in their world, where they are wanted criminals instead of heroes. However, their own in-fighting causes them to trap themselves instead, destroying the mirror in the process. The Saturdays leave Mesoamerica in their airship, unaware that the evil Zak Monday and Komodo have managed to escape from the fragments.

The Saturday family and King Ulraj travel to New Guinea to investigate the Duah, a pterosaur cryptid that has recently been causing trouble for the locals. The Saturdays discover that the creature was trying to attract a mate, and has chosen Zon. Zak tries desperately to separate the couple, in fear he will never see Zon again if she chooses to go with the cryptid. When the family and Ulraj learn of the Duah's plot to take his new bride to the underworld and eat her alive, they try even harder to bring Zon back to the airship. When the island begins to sink, Ulraj tells Zak that his cryptid powers only work if the creature truly wants to do what is asked of it. Zak manages to break Zon out of her crush and send the Duah back to the underworld.

Doc is visited by the ghost of his deceased mentor, Dr. Lancaster, in the form of an EVP. The family goes to the Honey Island Swamp complete what remains of his work: a database cataloging the DNA of every cryptid on Earth. While Doc and Drew finish the project, Zak, Fiskerton and Komodo explore the bayou, earning the ire of a number of humanoid cryptids (consisting of Momo, Bishopville Lizard Man, the Honey Island Swamp Monster, Lake Worth Monster, Kinchafoonie Creep, Georgia Pigman, Bardin Booger, Man Cat, Devil Monkey, Green Goon, Hawley Him, and Mississippi Swamp Ape). After repelling the cryptids, Doc and Drew continue their work, unaware that they are aiding a group of rouge government scientists. Zak, Komodo and Fiskerton are captured by the scientists led by Dr. Lee and fused into a hybrid creature. When Doc and Drew look for Zak, they run into the scientists who Doc identifies as the colleagues of Dr. Lancaster when they worked with him on a secret Cryptid super-soldier project. The scientists intend to make the Saturdays use their blimp as leverage to have the scientists' device taken out of the area in exchange that they restore Zak, Fiskerton and Komodo back to normal. Just them, the cryptids which attacked previously return in force which the resulting attack freeing the Zak/Komodo/Fiskerton creature. Doc and Drew had to trail the Zak/Fiskerton/Komodo creature through the swamp and managed to subdue it. They then learn that the Cryptids are shown to be capable of speech. The boys are returned to normal thanks to the Lake Worth Monster forcing Dr. Lee to restore them to normal. After listening to a recording left by Dr. Lancaster, the family decides to destroy all records of the cryptid super-soldier project, hand Dr. Lee and his scientists over to the authorities with evidence of their criminal activities, and return home.

V.V. Argost and Munya retrieve Leonidas Van Rook from prison, so that he and Piecemeal can kidnap Fiskerton, whom Argost believes to be Kur. They lure the Saturdays to Switzerland with a fake Buratsche-ah-llgs, a lake monster cryptid that appears to be a mass of unformed tissue. During the ensuing battle, Doc charges Fiskerton with protecting Zak, believing that his son is the target. When Zak and Fiskerton are trapped on a runaway train heading for a dead-end, Argost reveals that Fiskerton is the true target, and the gorilla-cat should turn himself in for Zak's life, which Fiskerton does reluctantly.

Zak and Doyle help Fiskerton to uncover the secrets of his Lemurian heritage with the aid of former Secret Scientist Abbey Grey, an expert in ancient civilizations and Zak's babysitter when he was young. They travel to the hidden archives of Alexandria in Egypt, where all information on Lemuria is stored. The knowledge gathered here leads them to Shangri-La, where a telepathic stone reveals that Fiskerton is meant to guard the world against Kur's evil. Rani Nāgi attacks the group to eliminate Fiskerton, but is repelled by the stone. With the truth about his people uncovered, Fiskerton decides that it's time to tell Doc and Drew.

Doyle takes Zak to an abandoned tourist resort in Canada for a training mission about deception, but they soon discover that the town is abandoned for good reason when the nearby lake, the Hînqûmemen, comes to life and attacks them. Doyle decides to distract the lake while Zak gets help, assuring him that he has a reserve oxygen tank with plenty of air. Zak quickly realizes that Doyle was exaggerating about his oxygen supply in order to keep him safe and returns to rescue Doyle with a wheelbarrow full of quick-dry cement, which turns parts of the lake into stone. Zak and Doyle make their escape, then arrange for cement to be dropped in the lake by helicopter. When they return home, Doc reveals that the water was infested with tiny cryptid parasites.

After listening to the cryptic advice of V.V. Argost, Zak urges his family to head to Mexico to deal with the Ahuizotl. But during a mini-vacation before going on their search, they are ambushed by Miranda Grey and Deadbolt. After the battle, they then wander into jungle village where the majority of the villagers have lost their eyes. The Saturdays split up, and Zak sneaks off to find the Ahuizotl. The Ahuizotl attacks the family, but a young girl from the village named Tiacapan comes to their aid. As the Saturdays ward away the cryptid, Tiacapan reveals that the village is going to sacrifice Miranda to the beast. After saving her, in the ensuing battle, Zak discovers that he can now sense the movements of cryptids. Using this to re-seal the cryptid into its tomb, the family leaves and Zak is forbidden to watch TV due to using "Weird World" as an excuse to go to Mexico.

After recovering the Epic of Gilgamesh, the Saturdays learn about a sect of Indian sorcerers who were able to drive out the spirit of Kur in the past, and they attempt to find them, in hope that group can do it again. However, they were attacked by the Secret Scientists again, but managed to escape. Eventually, they met Gokul who is the headmaster of the Legion of Garuda. They learned that in order to drive out the spirit of Kur a ritual, using an artifact known as the "Flute of Gilgamesh", must be performed. Unfortunately, the Nagas had stolen the artifact millennia ago. The Saturdays successfully retrieved the artifact and the ritual was carried out. Unfortunately, it was revealed midway that driving out Kur's spirit meant killing him; especially since Zak is Kur himself rather than someone possessed by him. And if that happens Zak will die along with Kur's spirit. The Saturdays, the Secret Scientists, and the Nagas teamed up and saved Zak from this fate, but Gokul had escaped. After they left the site, Argost came and took the flute.

While the Saturdays are resting in the Sahara Desert, Epsilon and Francis show up saying they want to recruit Kur. Epsilon tells Zak that Francis will be the one to train him. When Zak declines they decide to take him by force. Once the Saturdays get on the airship Zak tells his parents that he wants to help a cryptid because he "wants to do some good" and they go to Istanbul to extract the Lake Van Monster. But the operation hits a snag when Epsilon and Francis show up again. Drew and Doc want Zak to run, but he is determined to help the cryptid, saying that is what they do and that he needs to help something instead of running. Epsilon's "people" have a satellite with the Naga's Kur detecting relic in it, helping them find Zak wherever they go. Doc uses the Griffin to go up into space. After find out that Epsilon's people have a giant space station floating in space, Doc locates the Naga's Kur detecting relic and destroys it. Francis finds Zak trying to help the cryptid and says he is "painfully predictable". He then reveals that he is not Epsilon's son, but they are both clones of their people's best agent from one hundred years ago. Francis lets Zak escape and Zak sets the Lake Van Monster free.

Zak's birthday party is filled with surprises including a visit from Ulraj and Wadi. The Saturdays find out a town is being attacked by cryptids. When the Saturdays come to investigate, they are attacked. Zak's crush for Wadi and hers for him are made more open in this episode. Zak later encounters Argost in a clock tower, who hints at Kur's ability to control an entire army of cryptids from long distances. Zak, Wadi and Ulraj pursue the cryptids underground. Eventually, they fell into a pit that starts to fill with dirt. As they were being buried alive, Zak remembered Argost's words and managed to summon one of the cryptids to save them. The three soon learn that the cryptids were actually making a survival colony to save themselves from Kur. Realizing this, Zak assures the cryptids that he has no intention to harm them or anyone and ultimately earns their trust. Zak returns to the clock tower to thank Argost, who then gives Zak a neural parasite to contact him with should the need arise despite Fisk's objections.