Floating on the Seine is a very special barge: a bookshop tended by Monsieur Jean Perdu, a brokenhearted bookseller nursing his decades-long heartache by “prescribing” must reads for the patrons passing through Paris. This literary apothecary has medicinal tales for young idealists, overworked businessmen, widows starting over. Perdu presides over the bookshop like an eager pharmacist, ready with a recommendation at every turn.

Long accustomed to a solitary life, Perdu isn’t prepared for the sudden appearance of an equally vulnerable — and beautiful — neighbor. Believing his one true love, Manon, to have abandoned him 20 years earlier, Perdu has thrown himself into work . . . and scarcely looked up until Catherine arrived on the scene.

When their burgeoning relationship awakens old feelings, he panics — and runs. The floating bookshop takes its inaugural run. Accompanied by a young writer in a slump and many friends he picks up…