Henry "Monty" Montague was bred to be a gentleman. His passions for gambling halls, late nights spent with a bottle of spirits, or waking up in the arms of women or men, have earned the disapproval of his father. His quest for pleasures and vices have led to one last hedonistic hurrah as Monty, his best friend and crush Percy, and Monty's sister Felicity begin a Grand Tour of Europe. When a reckless decision turns their trip abroad into a harrowing manhunt, it calls into question everything Monty knows, including his relationship with the boy he adores.

Henry Montague, dit Monty, est un héritier qui passe son temps à jouer, à boire et à séduire, au désespoir de son père. Après son tour d'Europe, il est censé reprendre les rênes du domaine familial. Mais son goût insatiable pour tous les plaisirs l'enchaîne au vieux continent, où, en compagnie de son meilleur ami Percy, dont il est épris, il se voit bientôt pourchassé par son père.