When the children find out that in Constance's time they are killing seals for their oil they are more than a little angry because the result is there is none left in their time. A seal trapper gets more than he wants when Aunt Lily decides that she has to have him, and the children try and persuade him to stop killing seals. When a sick pup turns up, Mandy believes the only way to save it is by taking it through the mirror. (thetvdb.com)