The TV series revolves around the adventures of Justin. In every episode, Justin encounters a problem of everyday childhood (such as sharing, teamwork, or paying attention). Then Justin and his shape-shifting sidekick Squidgy solve the problems by tackling them in adventures through time and around the world. In every adventure, Justin and Squidgy meet their best friend Olive, who always lives in the place and time they are visiting, and who usually needs their help to accomplish a task. Together, the three of them encounter the same problem that Justin faces in his world, and together they solve the problem before he gets called back by his parents to his world.