The lives of Five-0's informants are in danger when the HPD system is hacked and one ends up dead, forcing McGarrett to enlist the help of hacker Aaron Wright, who he just imprisoned.

The murder of two tourists leads Five-0 to a man suffering from multiple personality disorder, where one of them becomes violent and another is a child. McGarrett is accompanied on the case by a stress management consultant, whom Danny and the others have hired to help him manage his health.