Ex-con and martial arts master Mason Sato terrorizes Mitch, Kaye, and Hobie.

Mitch Buchannon didn't die in a boat explosion in the 10th season but has been recovering from amnesia in Los Angeles. Mitch returns to Hawaii to get married again! His new fiancée Allison looks a lot like Lt. Stephanie Holden, a past love. Little does he know, Allison is cooperating with Mason Sato who appeared in the show's 2nd season and now returns for revenge. The Baywatchers are invited to Hawaii by CJ. She's opening CJ's Bar & Grill at the Turtle Bay Resort. Coincidentally, Caroline Holden is already there filming a soap opera. Neely Capshaw (ex-Mrs. Buchannon) comes to Hawaii to stop the wedding. She wants Mitch back!