"The premise starts with a thief, wizard, and knight finding themselves at something called Astral Academy, which houses an "ancient object" known as a trine. All three characters end up getting caught inside the trine, resulting in a situation where only one character can leave it at a given moment.
It's a story built to provide gameplay, basically.
When playing, you can switch between the three characters at any time with a click of a shoulder button. As you would assume, each character has a different set of skills: The knight's sword and shield make him useful in combat. The thief can hit foes with a crossbow, move quickly, and use a hook to attach to objects and swing around."