5.4Movie Scooby-Doo! The Mystery Begins (2009) Sep. 12, 2009 Scooby-Doo! The Mystery Begins (2009) IMDb: 5.4 2009 82 min 11716 views Watch Scooby-Doo! The Mystery Begins (2009) full episodes online free watchcartoononline. Synopsis: The story of how Mystery Inc. was formed. AnimationComedyFantasyMystery