McGarrett plays cat and mouse with a smart and seductive therapist he believes murdered her patient. Meanwhile, Catherine must hunt down one of Doris's old targets who is now seeking revenge.

A real estate agent is found dead inside the walls of one of his listings. Meanwhile, Danny's mother makes an unexpected visit and brings with her some shocking news.

Five-0 goes on a manhunt when a deliberate chemical spill enables six dangerous inmates to escape, including Kono’s husband, Adam.