Hall of Justice: 
Batman walks over and opens the doors, and leads the young heroes inside "More shall be here soon, however a problem has arose, a laboratory called Cadmus Labs has mysteriously set on fire, but we are needed to help against a ground of villains trying to destroy our sun...so stay here." 
Batman and the others walk over to a metal door like thing, slowly it says a letter, number, and name, before they disappear in a flash of light, slowly leaving the room so that it's only the two sidekicks, and hopefully the others will arrive soon.

Cadmus:
Dubbilex stands, waiting for the heroes, he needs to show them something. Slowly the fire trucks begin to spray water...but that will not help...