The second part of Free!: Timeless Medley. The Promise (約束 Yakusoku), is one of the compilation films of the show's second season, Free! Eternal Summer, with new additional footage and redone scenes. Sosuke Yamazaki, Rin's best friend from childhood, transfers into his class at Samezuka Academy. Rin and Sosuke had promised each other as children to continue their swim careers together, but unbeknownst to Rin, Sosuke has incurred a serious shoulder injury from overuse, yet continues to swim as they prepare for upcoming tournaments. While Rin is serious about swimming, Sosuke struggles to find a reason to continue, further straining their friendship. (thetvdb.com)