In the season premiere, McGarrett refuses to listen to Danny's pleas to take it easy while recovering from surgery after the body of a serial killer is left in the Five-0 headquarters with an ivory chess piece in his mouth. When a second serial killer is found dead with another chess piece, Five-0 goes on the hunt for the vigilante as fear grows that it's not safe to travel to Hawaii. Also, MacGarrett finds comfort in talking to someone with a very special connection to the team. Rosalind Chao recurs as Governor Keiko Mahoe, and Claire Forlani recurs as Alicia Brown, a retired criminal profiler.