Grandpa shows up to introduce his family to his new girlfriend – Sally Rasmaussen!  Thea and Benjamin are convinced Sally is just using Grandpa to get control of the company, but Geronimo refuses to assume the worst in people without proof.  Unfortunately, after following Sally around, they get all the proof they need.  It turns out she’s been hypnotizing Grandpa.  Can the Stiltons snap him out of it before the wedding?