Twins Georgia and Adam can't wait to go on their holiday to Cornwall - especially as it's the first time they're taking their new puppy, Lucky, with them. Lucky loves the seaside - chasing the waves, digging in the sand and the long cliff-top walks. One morning, unable to wait for Georgia and Adam, he sets off on his own. Unaware of the dangers, Lucky falls down a cliff and finds himself stranded, alone and hungry, and in need of rescue. Meanwhile, the search is on to find Lucky, but no one seems to have seen the little dog. How will Georgia and Adam ever find Lucky?