The Executive Officer joins HMAS Ambush and on a visit to Humbold Bay tries to match the Matron drink for drink. Later, Ambush apprehends a fishing vessel.
An expert with a past is assigned to assist Ambush with the destruction of an untethered WWII mine. He and his biggest critic skillfully collaborate to diffuse both the mine and a host of inter-related political and personal issues.
A maor naval exercise involving an aircraft carrier and four patrol boats brings Lt. Keating into open competition with his brother.
After Ambush encounters a craft displaying SOS, the Swain has to deliver a baby under radio guidance.
Ambush is heading for Cairns until a sudden signal puts her on unexplained duty for another six days.
After visiting his ex-wife, the Buffer has to pretend to be "Uncle Ken" rather than tell his son the truth.
Commander Keating suffers consequences to his career after having Ambush zealously pursue a drug smuggler.
Chef Borgia goes absent without leave while trying to help a girl escape from a prawn trawler.
The heir to the throne of a small Arab nation joins Ambush as a midshipman. Complications arise when he falls for a young woman who is a member of the crew of a small freighter currently in port.
Keating and Fisher have their nerves stretched by the presence of journalist on board HMAS Ambush.
The crew of Ambush transfer to a newer, bigger boat, the HMAS Defiance, while the X.O. takes his C.O. qualifying course.
Defiance engages in a war game against a group of commandos that causes the sub lieutenant to invoke a skillful tactic.
A well meaning padre thwarts the attempts of the Defiance crew to party with the Humbolt Bay nurses.
A sentry fires at what he believes to be a shark when the crew of Defiance is taking a swim. The round injures a crew member.
Defiance intercepts an illegal fishing trawler that later evades them, while the Sub Lt's wife tries to adopt a neglected boy member of the trawler's crew.
The crew of Defiance steal the army's crest.
Beyond his control the C.O becomes committed to two women at the same time and the X.O has to come to the rescue by entertaining one of them.
After a Christmas Eve performance examination, the Defiance crew are ordered to investigate the origin of an uninhabited yacht found adrift.