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.
A woman steals a book from a powerful man and hides out from him with the help of Eddie. Craig and Gina contemplate having children when they are married but have second thoughts after meeting a couple while on a romantic weekend. Trevor discovers that his hardest competitor among the rookies is doped.
Eddie does not like Shauni's new boyfriend or the way he treats her when things do not go the way he wants. Also Hobie gets in trouble with a girl who likes him.
A new hotel opens near the beach and a string of murders occur around the same time which convinces Craig the two may be connected.
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.
Mitch attends his high school reunion and meets a classmate that stirs up old feelings. Eddie, frustrated at having no car, buys one at an extremely low price from a buddy but quickly discovers the reason why the cost was so low.
A pro-am beach volleyball tournament is being held and Trevor tries to convince Jill to be his partner for the competition. Their main rival in the competition is Jill's ex-partner which cements Jill's resolve to compete.
A new lifeguard arrives at Baywatch and stirs up different emotions for the current staff. Jill and Shauni go into business selling sandwiches but find competition to be stiffer than expected.
Craig joins Cort and Eddie on a trip to Mexico for a long overdue vacation but things turn out very differently from their expectations.
Cort and Eddie go to a local water theme park to teach teenagers about lifeguard duties but one of them quickly resents Eddie's presence. At Baywatch, Hobie finds out that parents of his fellow students at school have a dim view of the occupation of lifeguarding and Shauni gets into trouble over her pinup magazine pictures.
An illegal offshore casino causes problems for Cort and some of his fellow lifeguards. Hobie thinks his English class is going to be a breeze when Mitch starts dating his teacher but soon learns otherwise.
Eddie believes he sees a ghost by the water and the others believe that he is losing his mind. Hobie learns that a friend's pet is going to be euthanized for an alleged attack and resolves to help both of them.
A local business owner organizes a shark derby but the event quickly spirals out of control and leads Jill to run into the water to save a little boy but then is attacked by the shark.
Cort enters a race to win the prize money and fulfil a pledge he makes on a yearly basis.
Mitch, Craig and Garner go on a hang gliding trip that results in a series of accidents for all three.
An earthquake shakes Baywatch headquarters and causes many problems for the lifeguards and for one, a life altering decision is made.
