Complex sentence: After seeing Henry the Octopus and his Underwater Big Band, they happen upon Brrrrrrrrrr Street where they get frozen; since they have no luck finding Dorothy, they go to Wigglehouse.
Split into simpler sentences: After seeing Henry the Octopus and his Underwater Big Band, they happen upon Brrrrrrrrrr Street where they get frozen. Since they have no luck finding Dorothy, they go to Wigglehouse.