At Oahu's North Shore, captain Sonny Jennings and his core team of lifeguards monitor the dangerous Hawaiian waters. Meanwhile, the new lifeguard recruits compete to join Sonny's district.
A flash flood sweeps a young tourist away from her family and out to deep sea; going against Sonny's wishes, Em takes a bold risk and places her own life in danger in hopes of rescuing the lost-at-sea tourist.
Em strives for team respect as acting boss. Hina and Kainalu handle beach emergencies. Will's fiance visits him at work. Sonny confides in ex-lifeguard about nephew's loss. Laka flirts with EMT Jenn.
College kids face danger in a collapsed sandpit. At sea, rescue efforts after a shark attack. Firefighter candidate Will awaits job results. Em attracts Fire Captain's interest. Hina pursues Kainalu.
Lifeguards face hazardous ocean conditions. Sonny appoints Laka as acting lieutenant. Kainalu's father urges him to leave shift for his political campaign.
Hawaiian lifeguards respond to an influencer swept into the ocean while filming, Kainalu and Hina set boundaries at home, Will's fiancé doesn't want Em at their wedding, and Jenn agrees to a date.
Christmas cheer is in the air as the lifeguards prepare for their annual holiday toy drive; while surfing, a local grandpa has a heart attack and is rushed to the hospital; Sonny tells Laka he is not ready to become a lieutenant.
Captain Sonny and the team face their most dangerous rescue yet when a minefield is discovered on the ocean floor. Meanwhile, on the beach, a hugely popular influencer will do anything to capture viral content for her massive following.
After stealing a cracked canoe, the team searches for two missing teens stranded at sea. Will clashes with District 7's new member, while Em gets an unexpected visit from her estranged mother.