As the first Protection card that features the word "threat" I think whether or not this card is any good seems important. A one cost event that removes 4 threat but only on the main scheme seems anywhere from Okay to Good. Fortunately there are a ton of already great cards that synergize with this. Notably this seems particularly good for Spiderman.
If the enemy isn't stunned, Webbed Up, or for whatever reason unable to initiate the attack, he immediately draws a card to soften the cost. Backflip lets him dodge the damage from the attack completely, and he has a killer base 3 Defense stat that you can just exhaust to defend and, in a way, just letting him Defend as a Thwart. Within protection you could use whatever combination of Desperate Defense, Never Back Down, Electrostatic Armor, Energy Barrier, Preemptive Strike, Defensive Stance, and Side Step to soften the blow and/or dish a little back at the villain, and combine those with Unflappable to get yet another card draw out of it. Failing all of those myriad options, let the attack crack you square in the face and immediately flip to Peter Parker to spend some time back at home with Aunt May.
Ms. Marvel is another great option. Her ability can refund the cost of the card like Spidey, she has a great damage reduction card Wiggle Room in her kit, and has high Recovery and amazing Alter-Ego cards that favor swapping frequently.