The Round Table's surviving members has dwindled to a handful after their abortive search for the Holy Grail, so they head back to Camelot. The tension between Lancelot and Mordred prompts Arthur to demand that his knights make peace with one another. However, Lancelot is secretly having an affair with Guinevere, and the king has no idea. Mordred plans to exploit Lancelot's infidelity as a weapon to bring him down, and the knight is split between his loyalty to the king and his feelings for the queen.