This film is about a few days in the life of Libby and Sarah, two elderly widowed sisters who have returned again to their seaside house in Maine for the summer. They have been whale-watching there every summer for several decades, even though the whales no longer pass close to the house. Sarah, who's older, is the primary caretaker of the two as Libby can hardly see anymore. She is mild, gentle, pacifying, while Libby is rigid, sour and self-centered.
The sisters are frequently visited by Tisha, their long-time friend and neighbor at the place. Glad to see them again, Tisha often brings up old times, which the film shows in flashbacks, allowing viewers to contrast the younger Sarah and Libby with how they are now. Sarah is seen as engaged as ever in finding life's joys, treasuring memories of her happy marriage and developing a gentle flirtation with Mr. Maranov, an old Russian gentleman who comes to fish near their residence. Libby, on the other hand, has withdrawn into her blindness and seems to be waiting for nothing but death. She resents her sister's receptiveness to Maranov and interferes with the budding romance, such that Sarah, who had always been grateful to Libby for support after her husband's death, considers giving up on her, selling the house and placing Libby in a rest home (as suggested by Tisha). These are black thoughts for the positive Sarah, who is especially vulnerable on the eve of her 46th wedding anniversary, but in a surprising scene where Libby, despite her near-blindness, "sees" something of Sarah's life, the bond between the sisters is rekindled.