Emilia, a law-school graduate, falls in love with her married boss, Jack. After Emilia marries Jack, her happiness turns unexpectedly to grief following the death of her infant daughter. Devastated, Emilia nonetheless carries on, attempting to forge a connection with her stepson William and to resist the interference of Jack’s jealous ex-wife.
Though Kevin has evidenced 23 personalities to his trusted psychiatrist, Dr. Fletcher, there remains one still submerged who is set to materialize and dominate all the others. Compelled to abduct three teenage girls led by the willful, observant Casey, Kevin reaches a war for survival among all of those contained within him — as well as everyone around him — as the walls between his compartments shatter apart.