A Vow Between Men (男と男の誓い Otoko to Otoko no Chikai) is the fourth episode of Ultraman Leo.
Leo is defeated, and Dan trains Gen even harder. Unfortunately, the monster won't wait.
When we last left Ultraman Leo, his color timer had run out after a seemingly fatal blow from Tsuruk sent the L77 savior into the sea. Believing Gen Otori to be dead, Dan Moroboshi ponders what to do next. Amazingly, Gen is found alive some time later. Dan castigates Gen, ordering him to remain in his human guise till he's mastered his triple attack regardless of when Tsuruk appears again. Unfortunately for MAC and Japan, the monster returns sooner rather than later.
Ultraman Leo Volume 1 features episodes 1-4, & Complete DVD-Box features all episodes.