Boku no Giovanni

A young Tetsuou watched a performance by Giovanni Bazonni and was inspired to become a master cellist. But he knows that living as he is in an out-of-the-way Japanese island means his musical aspirations are unlikely to be realised.
One day, a boy named Ikumi comes to stay at Tetsuou's place. Ikumi is the sole survivor of an accident at sea, wherein he saved himself by swimming out to Tetsuou's island.
But he makes a surprising claim: he says he found his way to safety by following the sound of beautiful cello music, and is convinced that the player was Tetsuou.