While watching over the Ironman Triathlon, J.D. and Sean must perform a rescue of two divers who have come face to face with a tiger shark. The reason the shark is so close in land is that Blake, a nefarious "shark tour" provider, had been dumping chum in the water. Sean, of course, is livid and becomes even more so when locals tell him not to interfere. Sean confronts Blake face to face, but Blake is not intimidated by Sean and even threatens him back. Unbeknownst to Sean, Kekoa and J.D. have continued their affair. They have, in fact, ramped it up to the next level, even though both know that what they are doing is dangerous and not in the best interests of the team.
This long-running series follows the adventures of a team of lifeguards on the crowded beaches of Los Angeles County. Veteran lifeguard Mitch Buchannon watches over the younger lifeguards that come and go with each passing season as they keep the beaches safe for vacationers. Frequently he must take action to save them from the raging seas and from the raging tempers that sometimes flare up between the young guards in this stressful job.