When Will accidentally creates a mysterious portal during a trip to the zoo, he's transported into the world of the Night Zoo, and thrust into an incredible adventure.

Joined by his friends, Sam and Riya, Will journeys to Fire Desert, where rumours of a creature called 'the Grip' have struck fear into the hearts of the animals. Even Captain Claw, a fierce lioness, seems to be acting strangely on hearing the news.

Will journeys through a new portal and arrives within the high walls of Igloo City. It is a strange place where the animals follow strict rules put in place by their leader, Circles the owl.

Will, Sam and Riya travel to the Tusk Temple in search of Maji the time-travelling elephant. But the temple is in danger. The only way to save it is for Will to undergo the Night Zookeeper trial - facing leaps over bottomless caverns, impossible puzzles, and an ultimate test in bravery.