As we saw in Super Sons #11 (also written by Tomasi and Gleason, with art by Ryan Benjamin and Richard Friend), Jon has inherited his father’s super flare ability. Introduced by Geoff Johns in the New 52 “Men of Tomorrow” storyline (there’s that word again), the super flare allows Superman to release all the solar energy he has stored in his body as a single concentrated burst. An extension of his heat vision, the super flare is a last resort as it not only renders Superman unconscious, but also depletes him of his super powers for the 24 hours it takes his body to replenish its stores of energy.
There’s a further catch for Jon. Being half-human, he can’t control the super flare, and it can emerge unwanted at times of extreme physical or emotional stress. His inability to keep it in check poses an existential threat to the world, which has put him in the future Batman’s sights.
Jon’s weakness creates an advantage for Tim. In a showdown at the Fortress of Solitude, he realizes that he can kill Jon without laying a finger on him. All he needs to do is to let the boy—who was weakened by an initial flare-up, and who is now in a trance caused by emotional overload—consume himself in a second super flare.
As Superman works with the present and future Titans to save the boy, the unexpected happens, and the super flare becomes independent of Jonathan. The fatalistic Tim sees a chance to save the future while sparing John. Absorbing the power unleashed by the boy, Drake is pushed back into Hypertime, but something is... different.
Instead of flashes of the moments he’s tried to alter, we see key images from the various Crises that have reshaped the DC Universe, including Barry and Wally hugging at the beginning of Rebirth, and Superman carrying the corpse of Supergirl at the end of Crisis on Infinite Earths.