Wolfie trains Oso to pilot a submarine. But Oso forgets to close the hatch, causing the water to seep inside Wolfie's submarine and sinking it. That's when a special alert comes in. A girl, Lena, accidentally breaks her grandma's flower vase while taking her dog Bo outside. Lena lets Bo take the blame, and she feels bad for not telling Grandma what really happened. So, it'll be up to Oso to show Lena how to tell the truth about the broken vase to her grandma and also apologize to Wolfie for sinking his submarine.