It’s a veritable FF convention in these issues. (Hey! Where’s the Mole Man?)
The Frightful Four (actually just three) have taken over the Baxter Building and are looking to complete their quartet with super-villain “try-outs.” Candidates include the Texas Twister, Captain Ultra, the Osprey, and others. The Fantastic Four show up, but are caught off-guard by the Trapster’s booby-traps and held prisoner. Thundra and Tigra both try to rescue the heroes when the mysterious Brute appears. With his help, the Frightful Four are triumphant and their group is complete.
A power outage, accidently caused by the Impossible Man, allows the Fantastic Four (and Thundra and Tigra) to escape. The Frightful Four and the Fantastic Four battle to the finish! But the Brute seems unstoppable, and Reed Richard’s powers are fading. Who is the Brute? Are Reed Richard’s powers gone forever? Will the heroes prevail? What does this all mean for the future of the FF?
Original collection; Current collection