Bob, Wendy and the team get a big surprise when Bob's father Robert comes to visit. When stern Ms Chalmers from the National Heritage asks Bob to renovate the old castle a case of mistaken identity leaves Bob's father in charge! The problem is, Robert is more of a hindrance than a help when it comes to doing the job. As Bob doesn't want to hurt his feelings he lets Robert help with disastrous consequences! Things really get out of control when they end up stuck in a dungeon. Robert finally makes it up to Bob... and creates a masterpiece in the process.