Episode Title:Castles in the Sky / Tipping the Scales.Episode Description:Castles in the Sky: The tree house collapses due to the weight of snow on it, so Arthur and his friends try to come up with their own designs to re-build it, while getting help from Frank Gehry.
Tipping the Scales: The school choir is excited about singing in Crown City, but they aren't excited about being taught by Arthur's strict piano teacher, Dr. Fugue.