Summary: The Silver Bullet, the fastest steam-powered train on the planet, is taking the rarest, most valuable stamp on the planet from Los Angeles to the Smithsonian in Washington, DC. The train is scheduled to stop in Tumbleweed Valley to take on water, where it will be guarded by one hundred Pinkertons and Riders In The Sky. Meanwhile, Slocum and Charlie have discovered a secret government experiment they stole is a virus that makes anything it comes in contact with invisible… featuring The Braun Brothers!
