Ensign Charles Parker reports for duty as the new Executive Officer of the PT 73, to a not-so-warm welcome from McHale and The Crew. But McHale is soon impressed by the Ensign, and persuades the boys to shape up, so that Parker can stay on as XO.

Lester Gruber has been given the job of laundering Captain Binghamton's uniforms. When a Japanese sub fires on the PT 73, the uniforms are destroyed, and Lester's finger is scratched, prompting him to put in for a Purple Heart.

McHale decides that what Ensign Parker really needs is a girl friend. He convinces Parker that he is suffering from an advanced case of battle fatigue so that he can be sent to the hospital, where McHale hopes that he will find Nurse Casey Brown to his liking.

Binghamton grants McHale and the 73 Crew a week's liberty in New Caledonia, but they must postpone their trip, when the 73 turns up missing, and they have to scheme to get a replacement.

When McHale and his men are assigned the duty of averting a Japanese attack on a US convoy, they use the soundtracks of movies starring John Wayne, Humphrey Bogart, and Errol Flynn to confuse the enemies.

McHale tries to figure out a way for Christy and his true love, Lt. Gloria Winters, to get married, even though it is against regulations for an officer to marry an enlisted man. But the lovebirds have even more problems: Binghamton schedules maneuvers on the evening of the wedding, and the Japanese schedule an all-out battle.

Chief Urulu demands monetary compensation from the Navy, for destroying the coconut trees on his island, and puts a curse on Binghamton, when he refuses to pay.

A plane with the Singing Tyler Sisters aboard is forced down with engine trouble on a deserted island. McHale and The 73 Crew are sent to pick them up, with more than their rescue on their minds, but wind up being quite disappointed.

Binghamton sends McHale and The 73 Crew on a recon mission to a supposedly deserted island, where they make a ‘Home away from home' to enjoy themselves, away from the base. But, the U.S. Navy, as well as the Japanese, become suspicious, when they observe unusual activity on the island.

McHale and the boys cook up a scheme to keep Binghamton from building a new Officer's Club on McHale's island.

Mchale decides for Christmas he and the crew of PT-73 will pay a visit to the Sister Monique and the children dressed up in a Santa Claus outfit and elf outfits. Mchale would parachute from a plane first and meet the kids and PT-73 would follow a little while after. Mchale jumps in his Santa outfit but when he lands he finds the island was overtaken by Japanese and was captured. Mchale as usual cons he's why through the itterogation and he claims that a new secret weapon is on it's way, just then PT-73 arrives singing Christmas carrols and dressed in elf outfits. The Japanese commander becomes scared fearing that this was some kind new of physcological warfare and he surrenders.

A Photo Journalist for the Office of War Information – An extremely unpleasant person, with whom McHale is familiar – Is sent to Taratupa to do a story on PT Boats and their Crews. Through a case of mistaken identity, McHale and the boys are stuck with her, and must scheme to try to get rid of her.

Binghamton's reputation as a ‘desk jockey' brings on a desire for some real combat experience, so, while McHale is away at New Caledonia, he assumes command of the 73, and goes out looking for action, with disappointing results.

A U.S. Congresswoman comes to Taratupa, to find a War Hero to take on a Stateside War Bond tour, and Parker and the boys help McHale to get chosen for the job, thinking that they will be going along.

Another of Gruber's shady enterprises backfires, when Binghamton gets a taste of the delicious Polynesian cuisine that Fuji has been cooking up, for sale to the base personnel.

Complications arise, when Gruber falsifies Parker's gunnery score to keep Parker from being shipped out.

Christy finds out he's about to become a Father, so, while McHale is away in New Caledonia, Parker and the boys come up with a plan to raise money for expenses.

The 73's engines are dying, and Binghamton uses the situation as an excuse to have McHale and his Crew reassigned. So McHale and the boys must scheme, to try to make the 73 healthy again.

Some local natives – Who depend on McHale and his men for their income – Are up in arms over Binghamton's having made their village off-limits to McHale and his Crew. But Binghamton must re-establish good relations with them, for the upcoming inspection tour of The Undersecretary Of The Navy.

Parker requests a transfer, when he feels he's not getting the respect he deserves. So, to change his mind, and build up his self-confidence, McHale puts him in charge of an important test mission.

The Navy has issued a directive stating that all overweight Combat Officers will be shipped out, and, when Binghamton goes all out to see that McHale goes over the weight limit, the boys cook up a plan to keep him with them.

A pesky Japanese Pilot – Whom the base personnel have dubbed ‘Washing Machine Charlie' – Is wreaking havoc, with his daily strafing runs on Taratupa, and McHale and the 73 Crew have an incentive to bring him down.

When a Japanese radio announcer broadcasts details about Captain Binghamton that only someone close to him would know, Binghamton immediately suspects McHale and The 73 Crew, and enlists Parker's aid in nailing the traitor.

Lovely Yvette Gerard has invited Parker to join her for a weekend at her island home. When Binghamton denies him leave, McHale works up a plan for Parker to have a ‘working vacation' on the island, which winds up with an unexpected bonus.

Trouble ensues, when Parker inadvertently invites three of the 73 Crew's Mothers – Including his own – To visit Taratupa for Mother's Day.