Stephanie's younger sister, Caroline, arrives in town for a visit with exciting news: she's engaged. But her fiancé, an environmental investigator, has a near-fatal diving accident that shatters her joy. Was it an accident or attempted murder? After Mitch performs surgery on an ex-con while still a hostage, he finds himself at the mercy of the wounded but dangerous man.
 

Mitch's upcoming birthday motivates him to enter an iron-man competition. He needs to show he can still compete with younger men. Meanwhile, Matt's effectiveness as a lifeguard suffers due to his new night job. His late hours make Summer suspicious since she doesn't know about the job. Standing in for a tired Matt, Summer is knocked unconscious attempting a rescue.