A group of children from diverse backgrounds are taken to a mysterious remote Scottish castle which houses a secret army research centre for an unknown purpose.
Noah and Luke Morelle arrive at World's End Castle and meet all their companions. Their mom (Amy Robbins) is immediately arrested and the twins are left in a state of panic.
Noah and Luke discover who has been watching them. It is their father who they thought was dead.
Stephanie tries to justify what she did to Noah and Luke. Gaia, AJ, and Slim try to banish the 'ghost'. Cat has a disturbing flashback.
Cat and Noah are caught by Lena and try to protest. The teenagers are allowed in the village for the first time.
Mackenzie and Skink scare Cat. Noah goes into Duncan's apartment to find a map and gets caught.
Noah and Cat connect and Adan Senior tries to spy on AJ. Gaia gets a nasty surprise.
Noah and Cat discover a hidden elevator. AJ has to explain to Mackenzie they aren't dating.
Noah and Cat try to find their way out. Lexy and Gaia clash as Gaia moves in with the winters. Luke is lost.
Luke has found a cave. Cat has another flashback and turns to Lexy for help.
Lexy has another flashback. Noah tries to discover why he doesn't have a birth certificate.
Slim is terrified after he sees his 'doppelganger'. Gaia Slim and AJ try to get rid of their ghost.
Lexy has strange memories of the SZ. AJ and Slim enlist Mackenzie and Skink to get rid of the Evil Gaia.
Somehow Gaia has escaped from the fire. Slim and AJ are punished by Lena.
Lexy and Cat find some of her mothers things in Duncan's room. Slim and AJ discover their 'twins' and Gaia's dad is puzzled with her behavior.
Gaia describes to the others what she saw in the SZ and Noah connects with Casey.
Cat tells Moira what is going on but then thinks she betrayed her. Noah tries to convince the others they can trust Casey.
Lexy and Cat sneak into the SZ. Lexy finds out some sad news.
Noah is shown a secret by Casey. Lexy and Cat nearly get caught in the SZ.
The teens try to work out whether Casey can be trusted. Casey tells Cat he has been her guardian.
Cat finds herself being assessed as part of the twins training missions. Caitlin discovers life outside the SZ.
The twins explain what they are doing and Casey is on the hunt for more Pictish Balls.
Cat discovers the Origin. Scared, Cat runs from the SZ. They try to find Caitlin to explain what has been going on. Gregor and Gaia connect and Caitlin gets a shock.
Noah, Cat, and Lexy discover something odd in Casey's room.
Noah, Cat, and Lexy are terrified by the picture they saw in his room.
Cat has disappeared and Slim and AJ tell the others what the discovered in the SZ. Gregor and Gaia continue to bond as they try to decode the SZ symbols.
The teens are excited as Lexy and Luke return with the Object. Noah and Cat connect. Casey is arrested after being caught by Lena and Major Javadi.
The situation is finally explained to the teens, but not with the results they were quite looking for.
After more revelations, everyone is left wondering about different things, especially Noah and Luke who are left wondering if one of them could be a clo-bot.
Noah and Luke take part in a competition against Luke and Cats will. The truth about who really is the clo-bot is becoming clearer to Noah, who decides, after being rejected by Cat to test it out by jumping off the castle wall.
Casey encourages Noah and Noah learns of what the clo-bots can do. After a showdown in the SZ, Lena takes drastic action, with bad consequences.
Noah enlists Slims help and Casey gives Moira an unfair choice about the kidnapping of Gregor and the scientists get a big shock.
The teens face a tough decision as they begin to pack for titan. But they wont stay to the rules for long. Casey needs a new way to get into the castle.
Casey finds allies in SZ Gaia and Noah and AJ slips out to see Mackenzie and Slim comes up with a theory.
Stephanie and Arcus work on Slims theory of Mirror Matter. AJ slips into the Village to say goodbye to Mackenzie and Noah makes a big decision.
Moira enters the castle for help as Casey has trapped Gregor. Lexy, Gaia and the dog help Moira to search for Gregor. Casey threatens the adults with some toxic gas and Noah has to decide if he will join Casey or help his mom.
Casey is on board Titan 2 and the rocket fires away. Skink and Mackajay find the castle deserted. The clo-blots, except for Noah, have some freedom before the World ends. The adults try to work a way to control Titan 2 hopefully blasting it into the asteroid destroying it. But Lena hesitates and Lexy is in for a shock at the end.