I can't believe you turned down the Justice League! 
Billy Batson and the Magic of Shazam! #21 is an issue of the series Billy Batson and the Magic of Shazam! (Volume 1) with a cover date of December, 2010.
Synopsis for "Commencement"
After Black Adam attacked the Rock of Eternity, and opened the scarab granting him augmented powers, the Marvel Family rallied against him as he grew in power and size. He manages to steal power from Mary Marvel, converting her into a powerless child but when he attempts the same on Captain Marvel, he finds that he can't—his powers are a gift from Shazam and cannot be taken away by Adam. Captain Marvel, Jr. and Tawky Tawny help Mary while Captain Marvel uses his new-found confidence to fight against Adam, combining all of his individual abilities in ways he didn't previously realize he could. Mary calls for the train that can transport them to the Rock of Eternity and Cap punches Adam into the train, bringing them all to an ailing Shazam. The wizard tells Mary to extinguish the flame in his brazier and keep it out for one minute. In this time, he transfers all his power—that which he gave to Adam and Captain Marvel—into Cap, converting his costume from red to white and allowing him to easily defeat Adam. Shazam congratulates them and says that he knows he can pass on into peace knowing that the world is in good hands. As he lies on the ground evidently dying, he says that he wants Cap to be his successor. Marvel disagrees and says that he has more to learn, calling down a lightning bolt that transfers power back to Shazam, strengthening him. Shazam traps Adam in the amulet once more and the Marvel Family flies away, encountering the Justice League, where Superman invites Cap to join. He declines, stating that he already has a family and the Marvels fly away smiling.
Appearing in "Commencement"
Featured Characters:
Supporting Characters:
- Mary Marvel
- Captain Marvel, Jr.
- Tawky Tawny
- Wizard Shazam
Antagonists:
Other Characters:
- Justice League (Cameo)
- Superman (Cameo)
- Batman (Cameo)
- Wonder Woman (Cameo)
- Flash (Cameo)
- Green Lantern (Hal Jordan) (Cameo)
- Aquaman (Cameo)
- Green Arrow (Cameo)
- Hawkman (Cameo)
- Hawkgirl/Hawkwoman (Cameo)
- Black Canary (Cameo)
- Zatanna (Cameo)
Locations:
Items:
Vehicles:
See Also
- Cover gallery for the Billy Batson and the Magic of Shazam! series
- Images from Billy Batson and the Magic of Shazam! Vol 1 21