This is "The Tide that Left and Never Came Back," by The Veils. Probably my favorite musical find in the last year or so, Finn Andrews, the virtual one-man-band behind the "veil" seems to be a bit of a musical genius. This song is off their first album, The Runaway Found ('04), which I had to buy from Japan. Ridiculous, but you do get two extra songs that way. Other songs to check out from that album:
In my layman's opinion, this band is seriously underrated.