Fisher, an officer in the Royal Navy, is currently stationed on Telemachus, a submarine in the Indian Ocean. He's often the butt of jokes, given his strange childhood. Fisher is also in love with his cousin Margery. He writes home, and to her, often. The Telemachus departs towards the Andaman Sea with no specific orders from HQ. They encounter a Dutch merchant ship that tells them the other fleet had abandoned hope and fled back to Kenya. The captain of the Telemachus decides to torpedo with what little ammunition they have rather than give up. They bide their time, eating a strange mutton for every meal, and trying to stay awake on their four-hour shifts. Fisher remembers the harrowing Norway patrols well; entire days spent entirely submerged, with only a few hours between bombing to come up for oxygen. The men's heaving breaths as oxygen ran low. Watching all the other submarine's lose to German firepower. Somehow the Telemachus made it though. After the Norway patrols, Fisher takes leave and his cousin invites him out for drinks. They talk about her brother Jimmy in the RAF and her friends from home. When they leave the pub, Margery pulls him into an alleyway and kisses him. He pulls away feeling wrong. The next morning, Fisher leaves for the East. They sail to Singapore, spend a night on land, and then head out to Colombo Harbor. There, Fisher spends time drinking with Petty Officer Mills. He receives a letter from Margery and then they depart once more. Positioned in the Bay of Bengal, Fisher is awoken by an explosion. Telemachus' captain has decided to fire at an ammunition ship. While the men are excited by the half-victory, firing has also given away their position. They wait anxiously until the blasts come. They're hit three times, each with damage, but by the end their enemies are moving away and Telemachus is alright. They head into open ocean and the men become restless. Mills begins to petition to return home. One night, Fisher takes duty on the bridge and tries to think how he'll respond to Margery's letter. The next day, a convoy is picked up and the captain decides to fire on it. Mills urges him not to, but they fire all of their remaining torpedoes. Fisher realizes what he wants to write to Margery about: a bale of sea turtles he saw once.