The plot of Book 7 is a familiar one. In it, Lancelot and Guinevere try not to act on their feelings for each other. But they are spending more and more time together in public, and Arthur’s court is beginning to gossip.
Then Guinevere is kidnapped by the evil lesser noble Mellyagaunce. An enraged Lancelot speeds to her rescue. Upon Lancelot’s arrival, Mellygaunce pleads with Guinevere for forgiveness, which she grants, and asks Lancelot to spare Mellygaunce’s life. Lancelot agrees, and spends the night at the castle. Here, Lancelot and Guinevere finally commit adultery. Mellygaunce suspects as much, and intends to tell King Arthur. But Lancelot fights him (out of fairness, Lancelot fights without his armor and with one hand tied behind his back), and kills him.