Complex sentence: It is only by chance that the two girls encounter Lincoln Cushman while waiting in line to ride a ferris wheel at a local festival, who overhears a conversation betwen the two girls who are discussing the difficulty of finding a keyboard player.
Split into simpler sentences: It is only by chance that the two girls encounter Lincoln Cushman. While waiting in line to ride a ferris wheel at a local festival, Cushman overhears a conversation betwen the two girls who are discussing the difficulty of finding a keyboard player.