This is Gem Club from Boston, Massachusetts and their album called Breakers was released earlier this year.
This video is apart of the "Watch Listen Tell" sessions. They have taped bands like Dark Dark Dark, Lucy Rose, Lissie, and Young the Giant.
I can find myself falling asleep to this song, everything is played just-so. The piano, the chimes, the tambourine, cello, and Christopher's voice - meld together perfectly.