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?