When L.L. Bear and his friends meet for a picnic on Blueberry Island, they end up searching for Simon the seal's nephew, Sam, who gets lost in a storm.

LL Bears Island Adventure is about a bear who kayaks out to Blueberry Island for his last picnic of the fall. He talks with many of his animal friends on his way there and they all meet him at the island. All except little seal Sam, he got separated from his uncle. LL Bear goes out into the storm and finds Sam. They all hang out for a while, then LL Bear gets into his tent. When he gets out it is snowy and all his friends say goodbye to him until the spring or summer.