At the request of the foundation, teenage rocker Shane G. joins the Thornberrys during their stay in Alaska. Since Eliza and Debbie both have a crush on Shane, they both go exploring with Shane only to discover who thick-headed he really is.
While Marianne and Nigel are off filming in Glacier Bay National Park, Shane and Eliza disobey orders and kayak into the bay to view a glacier that's about to calve. Nigel finds filming the rare blue glacier bear too easy.
Eliza lets jealousy over Shane and Debbie get the better of her commonsense, ultimately, endangering them all. Nigel and Marianne face one natural obstacle after another in their quest to get close to the skittish Dall sheep.