Mitch Buchannon has just been promoted to lieutenant. Mitch and his ex-wife Gayle have an argument about what's best for their son Hobie. Eddie Kramer is the top rookie in the rookie class of '89, and Shauni McClain is one of the last ones to qualify. Shauni starts off as a terrible lifeguard, but the experienced Jill Riley teaches her how to become a good lifeguard.

Instead of attending summer school, Hobie decides to go power skiing with two friends, whose recklessness leads to a tragic accident. Eddie's lack of financial resources is revealed when Craig finds him sleeping in one of the lifeguard towers.

Los Angeles is having a heat wave and it's going to be a busy day for the lifeguards.

An old acquaintance of Eddie's comes to L.A. but it quickly becomes apparent that Eddie does not welcome this visit. Trevor dates a rich woman that is a handful for him to deal with and Mitch worries about upcoming mandatory tests that all lieutenants, including him, must take.

Mitch's former wife is planning to move to Ohio and wants to take Hobie with her. Upset over the squabbling that ensues, Hobie takes off with a friend and runs into pirates on a nearby island. Eddie and Shauni squabble after Shauni accidentally hurts Eddie.

Gayle and Mitch continue to fight over Gayle's plan to take Hobie with her. She ultimately changes her mind after Hobie risks his life to save a drowning young girl. A plane crashes into the water near the beach with the occupants, after they are rescued, looking to recover a suitcase of stolen money that they had with them. Captain Thorpe decides to join Eddie and Shauni on their tower in order to teach them.

A man is found drowned off the beach and Jill suspects foul play is the reason. She begins seeing the son of the victim and during the investigation discovers the man's cousin was responsible for his father's death. A man who helped Jill bring the victim ashore decides he wants to be a lifeguard as well even though he is not qualified.

An approaching tropical storm has the Baywatch lifeguards preparing for its effects but the presence of two wanted criminals cause unforeseen events. Eddie and Shauni rest. Hobie and a girl have storm parties.