In 1945, the war has just ended. Anela is slated to return home to the Big Island from Honolulu in two days time, when she meets a dashing officer named Gene. It would seem that fate has brought the two together. But life has other plans and when Gene loses Anela, he turns to the sea in an attempt to keep her memory alive.
Meanwhile, when an old bottle washes into the backwaters of Puget Sound all Stella can think about is solving the coded message contained within. Surprised to discover the bottle rode the currents all the way from Hawaii, she embarks on a journey that will lead her to the place where it all began – Holopuni, an old beach-house on the rugged Kohala coast. There, she discovers who sent the message, but is still haunted by the question of why. Heath is a young local fisherman who Stella tries to think of as just a friend. He's too young for her, but something about his connection to the sea appeals to her on a deeper level and she finds herself inexplicably drawn to him. While searching for answers, the two are pulled into a fight to save Holopuni from certain ruin. What they find is a startling revelation from the past that turns Stella's world on end, and could also be the key to cracking the code.
Equal parts loss, love, and hope, Salt and Seaweed weaves together the stories of two generations of women, whose lives are intricately connected by the sea.