James Keaton invents a time machine and goes back seven years to try to thwart the plans of his rival, Frederic Nichols. Meanwhile, Keaton's neglected girlfriend, Leila Locke, finds the time machine and uses it to convince her younger self to not get involved with Keaton in the first place. While in the past, however, she falls in love with the younger Keaton all over again.
A decade after his heroic defeat of the monstrous Kraken, Perseus-the demigod son of Zeus-is attempting to live a quieter life as a village fisherman and the sole parent to his 10-year old son, Helius.
When an evil spirit known as Pitch lays down the gauntlet to take over the world, the immortal Guardians must join forces for the first time to protect the hopes, beliefs and imagination of children all over the world.