It's summer break for Mark and his friends, but supervillains don't take a vacation. Mark is forced to face the consequences of Omni-Man's double life.

After two challenging missions, the Guardians of the Globe struggle to work as a team. Meanwhile, Mark tries to balance his hero duties, personal relationships, and his future as a college student.

As Mark attempts to salvage his personal life, a new villain arrives, presenting Invincible with his greatest challenge yet. Donald grapples with his past.

An old enemy threatens everything Mark holds dear.