When one of Mum's icy experiments gets ruined by spilled water, she notices it looks like an ice rink. To Cosmo, ice skating sounds amazing! To finish her experiment, Mum must take her equipment to one of the coldest planets – planet Neptune. Dad is convinced they will be able to ice skate on Neptune but what they find is disappointing. Neptune is not smooth and solid. It has no solid surface at all. After another accident with water, Cosmo thinks of a plan that will allow them to ice skate after all.