11-year-old Bo is a naive boy whose only and imaginary friend is a luchador named M the Minotaur. The two are inseparable and set off daily to fly model airplanes. Their activities are disrupted when Susie, a young aspiring pilot, accidentally shoots down their aircraft. Out of regret she invites the pair to their first birthday party. However Bo's biggest fear is change. He tries his best to avoid any decisions but is eventually pushed out of his shell when his parents, Peter and Rebecca, decide to separate. The culmination of these turbulent events forces Bo to grow up and apart from his imaginary friend.