CapeZoneCapeZoneCrossover event · Marvel
The Avengers team up their Prehistoric selves and alternate versions of themselves to fight against Mephisto's army and a multiversal version of the Masters of Evil who plan to wreak havoc on the multiverse.
I read Avengers Assemble
The reading order, derived from the collected editions — what they reprint, in order.
The exact issues, where the data pins them down: the event's own series, plus tie-ins named by story arcs or collected editions.