Ape Escape: On the Loose provides players the challenge of capturing more than 200 monkeys in eight vibrant worlds spanning more than 20 levels in order to prevent them from changing history! When a trouble-making monkey named Specter gets hold of the Professor’s Peak Point Helmet, chaos ensues.

The powerful device, which can increase a human’s intelligence, has a disastrous effect on Specter, transforming him from a sweet, mischievous monkey to a power-hungry monster who has his heart set on ruling the world. The power of the helmet enabled Specter to break free from his cage while also allowing him to free hundreds of other monkeys at the zoo.

Specter and the monkeys escape to a nearby laboratory where the Professor, who created the Peak Point Helmet, is working on his latest invention, a time machine. Taking control of the laboratory, Specter and the other monkeys use the time machine to escape into the past.

The adventure begins when the player takes on the role of a brave young boy named Spike, a friend of the Professor. Spike’s mission is to pursue Specter and the monkeys who have fled to the past in order to prevent them from changing history and taking over the world.