Martin, a shy Englishman in his early 20s, is in Poland doing a field study on river pollution when he sees a woman and her son bathe in the river, a moment of pure joy. Later, he discovers that Ewa works at the guest-house he's staying at and he warns them not to bathe in the river due to the pollution from the nearby factories. Jacek, Ewa's son helps Martin with his research and he becomes something of a father figure to him. As a thank you for letting Jacek help him out Ewa invites Martin for dinner before he is to return home to England. Martin misunderstands the invitation and at the end of the night, a little tipsy, he tries to kiss her - but is rejected. The next day he speaks to a lab technician in the UK about the samples he's sent back for testing– there is some pollution but not where Ewa and Jacek have been swimming. When Ewa doesn't show up for work and still hurting from the rejection Martin leaves without passing on the message that the river is fine to swim in.