After looking at an Leonardo Da Vinci exhibit in the museum, Phineas and Ferb wonder what it would he was like as a kid. They use there time machine to visit Renaissance Italy, only to find "Leo" is a fragile boy. They accidentally take him back to the present, where Leo becomes interested in the modern day world. Unfortunately without Leo in the past, the modern world finds itself reverting back to the middle ages. Phineas and Ferb must find Leo and bring him back to his time. This article is a . You can help My English Wiki by expanding it.