In Tool Box 15 American Chopper is rocked as Paul Sr. and Paul Jr. go head to head in a no holds barred argument - resulting in Paul Jr's departure from OCC. But with bikes for Northrop Grumman and NHL on the lifts there’s no time to rest. The crew soon find themselves clowning around at the circus, and building a bike to honour the music festival held at Woodstock, all while adjusting to life without Jr. OCC also celebrates a milestone, with a 10th Anniversary bike designed for mass production but with Paulie and Senior's relationship rocky at best, Sr. decides it's time for family bonding and calls his son's in to work on a "just for fun" Triumph Bike. But it's not all happy days as the sparks continue to fly; this time Mikey goes head to head with Sr.