Unfair-Weather Friends

Nearing Fortree City, Ash and the gang are caught in a sudden snowstorm. When the storm disappears as suddenly as it came, the group discover that it was the work of a Castform, a Unique Pokemon which has the ability to change it's type and form along with the weather. This Castform belongs to the local Weather Research Institute, where the resident scientists study weather conditions. However the gang's tour around the complex is interrupted when Commander Isabel from Team Aqua (whom the group previously encountered on Dewford Island and Mt. Chimney) attacks the Institute attempting to get a hold of the data hoing it will lead her to the location of the legendary Pokemon that Team Aqua have been hoping for and it's up to Ash and Co. to stop the data from falling into such dangerous hands...