Complex sentence: Two years later, Kōsei hasn't touched the piano and views the world in monochrome, without any flair or colour, resigning himself to living out his life with his good friends, Tsubaki and Watari, until, one day, a girl changes everything.
Split into simpler sentences: Two years later, Kōsei hasn't touched the piano and views the world in monochrome, without any flair or color. He has resigned himself to living out his life with his good friends, Tsubaki and Watari, until, one day, a girl changes everything.