Five young people who demonstrate special powers are brought to a secret institution to undergo treatments they are told will cure them of the dangers of their powers. Included are Danielle Moonstar aka Mirage, who creates illusions from other people's fears; Rahne Sinclair, who transforms into the werewolf Wolfsbane; Sam Guthrie, who, as Cannonball, can fly at jet speeds protected by a force field; Roberto da Costa aka Sunspot, who absorbs and channels solar power; and Illyana Rasputin aka Magik. The younger sister of Colossus, Magik becomes encased in armor at will and wields a soulsword that amplifies her multiple superhuman and psychic abilities. Invited by Dr. Cecilia Reyes to share their stories about when their powers first manifested, the five "patients" come to understand that they are in a class of people called mutants, who have historically been marginalized and feared. As they relive their origin stories, their memories seem to turn into terrifying realities. Soon, they question what is real and what isn't, and it becomes clear that the institution isn't what it seems. Now the question is – why are they being held captive? And who is trying to destroy them?