Marvel's Hulk and the Agents of S.M.A.S.H. - Season 2 Episode 22 -

Chasing Leader through time to World War II, Hulk teams up with a young Captain America to stop Red Skull who becomes Green Skull when enhanced with gamma energy by Leader. In the present, the Agents of S.M.A.S.H. team up with an old Captain America to fight and free the world from HYDRA which is led by Leader and operating a device that is powered by Green Skull.