Saltwater summer is about a young man's first summer as a commercial salmon fisherman on the BC coast. Don Morgan is a seventeen-year-old who has made enough money trapping on northern Vancouver Island to buy himself a 32-foot West Coast salmon troller known as the Mallard. He thought this was all he wanted from life, now almost nothing about it was good. The fishing his first season began poor, and if things didn't pick up, the Mallard, which had only been his for three months, would have to be sold to repay old Shenrock for loaning him the money. Don collaborates with his friend, and fellow fisherman Tubby Miller, whom he had partnered with for years at Bluff Harbor School, and through trapping together during the previous winter.
The two pair up and proceed up north, to where they figure they will make their keep. Along the way, the two meet up with a few seasoned veteran fishermen. Among them are Red Haliday, and Tom Moore, who together share the duties of the Falaise. The four men quickly become friends and agree to meet up again once they reach Pendennis Island.
They run into old friends, from years ago, and solve many problems along the way, like how to stop two feuding Irishmen, without drowning their cat. Even though they split up for a while, and Don nearly gets arrested for shooting a buck out of season, Don and Tubby overcome their many trials and tribulations. As the fishing season draws closer to an end, a violent storm raises. A fisherman known as Old Cowbells is stranded out in the raging water. It is Don and Tubby, along with Tom who go to his aid, risking their own lives to save another.
Tubby agrees to stay on with Don, and the Mallard does not have to be sold. In the end, the life of these fishermen is really not that bad.
The story takes place along the BC coastline from the Fraser River up to Prince Rupert. It is not centered on strictly the ocean, but around the beautiful landscape and scenery they come to along the way. We find out not only about the shores and the water, but about the mainland, and surrounding forest as well.
The raging ocean becomes evident when Red says, "I've seen boils of water there'd make you think the whole ocean's coming up at you from the bottom" (Haig-Brown 31).