Gus's quest to find Birdie and uncover more about her connection to his father leaves him questioning everything he's ever known.

His world shaken, Gus runs off and makes a rash decision. Big Man comes to grips with long-ago mistakes. Aimee makes a last stand against General Abbot.

Locked up in the zoo's kennels, Gus meets his fellow hybrid prisoners as he looks for a way out. General Abbot pressures Dr. Singh to produce a cure.

After an eventful, obstacle-strewn journey to find a safe haven, Gus learns more about his origins and how far Birdie was willing to go to protect him.