Of the experience, Kath said, "I recorded most of the record in the coldest winter in decades in a church without heat in Iceland.It was so cold that when I listen back I can hear myself shivering. In December 2009, Kath gave vocalist Alice Glass a CD-R containing 70 instrumental tracks, for which she then recorded vocals on 35 tracks.This single also included a single mix of "Celestica".
In order to promote the album, the band released the first single "Celestica" in April and an EP titled Doe Deer was released only a few days later. The album reached number 48 on the UK Albums Chart and number 188 on the US Billboard 200.
Later on in December, the duo's cover of the Platinum Blonde song "Not in Love", featuring guest vocals from Robert Smith of The Cure, was released as the album's third single.
The single became Crystal Castles' highest-charting single to date.
Crystal Castles II received generally positive reviews from music critics.
The song is said to have some relation to the Canadian factory Celestica in which Ethan Kath said that one of the workers allegedly committed suicide by jumping into a tub of hot plastic and that they still used the plastic to make products.
The album was initially scheduled for release on the June 7, 2010; however, the release dates were moved forward after the album leaked online, thus a digital version of the album was released on April 23, 2010.