One Piece - Collection 21

The story of Luffy and Ace's past is revealed! As a boy of only seven, Luffy is reluctantly taken in by the Dadan family of mountain bandits where he meets young Ace and his friend, Sabo. Dreaming of becoming pirates, the three form inseparable bonds of brotherhood. But the impending arrival of a Celestial Dragon throws the kingdom into a frenzy as a sinister plan to destroy their home unfolds. Years later, after the tragedy at Marineford, Luffy questions his ability to become the King of the Pirates. His crew members, scattered to the farthest reaches of the globe, are determined to keep their promise and return to Sabaody Archipelago in three days. But when "Dark King" Rayleigh offers Luffy a stern suggestion, he must choose between reuniting with his friends or joining Rayleigh in training.