The multiverse was destroyed!
The heroes of Earth-616 and Earth-1610 were powerless to save it!
Now, all that remains is Battleworld!
A massive, patchwork planet composed of the fragments of worlds that no longer exist, maintained by the iron will of its god and master, Victor von Doom!
Each region is a domain unto itself!
Something was amiss in Yinsen City well before a costumed figure called Captain Britain illegally entered the walled metropolis. Like Captain Britain (Dr. Faiza Hussain), the Defenders who protected that domain had vivid dreams that they were in fact following in the footsteps of deceased heroes (Captain Britain and the Mighty Defenders #1).
Spider Hero (Hobie Brown), for example, had a vision that he gave up his pervious guise as the Prowler following the death of the original Spider-Man (Peter Parker).
Rescue (Ho Yinsen, baron of the city), dreamt that he had invented his suit of technological armor with a dying Tony Stark. (In the original Marvel continuity, it was Yinsen who died after helping Stark build his Iron Man armor in Tales of Suspense #39.)
Other Defenders in this timeline included Kid Rescue (Antonia Yinsen, the baron's daughter), White Tiger (Ava Ayala), and She-Hulk (Jennifer Walters). Also the Thor if this domain, She-Hulk carried a gavel instead of a hammer (suggesting her former career as an attorney).
As an aside, Prowler and the original White Tiger (Hector Ayala) were both Defenders for a Day.