The Marquis keeps his appointment but will not come inside, so La Motte walks with him into the forest and does what he thinks is wanted: he sells him Adeline. She is shut in her chamber, he says, and she can be his tomorrow night, or tonight if he likes. Each time La Motte names an hour, the Marquis circles away from it, until he says in a voice "scarcely human", "Adeline dies!" La Motte has spent the whole talk offering a prize, and now learns that the buyer wants her dead. The Marquis will give no reason, rules out poison because it cannot be bought safely, and hands over a poniard. He has also reminded La Motte of "a certain transaction" that binds them both to silence, and La Motte, seeing the choice between murder and ruin, pretends to agree. They plan the night: she is to be killed in her sleep at midnight, and the open doors of her chamber and the west tower will suggest that she fled from the Marquis's attentions.
Adeline, meanwhile, has spent the day shut in the tower chamber grieving for Theodore, a prisoner in chains because of her. At sunset she watches the Marquis ride away without knowing why he came. At supper La Motte's haggard face and wrong answers alarm his wife. At midnight he climbs the spiral stair with a lamp, his hand shaking so hard that he must set it down to turn the key, and he finds Adeline asleep, her cheek still wet, singing in her sleep a sad little air she once sang to him. The lamp wakes her and she begs him: "You once saved me from destruction; O save me now!" He tells her to dress and leaves her waiting while she hears voices and steps below. Then he leads her to a side door where Peter sits on horseback. He tells her to leave the kingdom for Peter's sister in Savoy, gives her money, begs her to say nothing of the abbey, and asks her to remember that he is "not quite so bad as I have been tempted to be".
Peter talks the whole way, and his artless concern ends her fear that he betrayed her before. They ride by way of Thiers, glimpse the Alps for the first time, and reach Lyons, where she avoids asking at the inn about the Rhone in case the Marquis traces her. They hire a boat upriver, a route she chose because she thinks he will not follow by water. At dawn, on the boat, she writes a sonnet about a morning that cannot lift a sorrowful heart.
Back at the abbey La Motte listens at the gate until the hoofbeats fade, then feels a lightness he has not known for a long time. Soon he weighs flight against a forged story in which only Peter helped her escape, and he stays. The Marquis arrives, curses himself and Adeline with a coarseness that astonishes La Motte, sends servants after her, and returns within hours with officers of justice. La Motte threatens to reveal that the Marquis wanted him to commit murder. The Marquis asks who would believe a man banished by his own crimes, and the officers seize him. Too late to help himself, La Motte gives up the road to Lyons. The Marquis lets Madame La Motte follow her husband in a carriage and sends his valet ahead to trace Adeline, so the La Mottes leave the forest of Fontanville just as a rider heads up the road they have named.
Coming Up in Chapter 16
Peter and Adeline land in Savoy, and Peter cannot stop praising his native mountains. At his sister's cottage Adeline falls ill with fever and sinks into delirium. When she wakes, the room around her is spacious and elegant, and a gentle girl is leaning over the bed to ask how she does.
