InsaneJournal

DCAU: When present Superman met Batman Beyond
This is from Superman Adventures 64. 22 pages total, posted 7 and the cover.

Terry gets sent back in time by Bruce of the future to prevent Clark from making a horrible mistake.

Basically Brainiac has launched this super nuke that could put the entire earth into a nuclear winter. Superman originally stopped this by throwing it into the sun and it worked...until the future when it eventually caused the sun to send solar flares towards earth, heating it more and more each day. Terry is here to stop that and instead of the sun Superman throws it into deep space where no one will ever get hurt by it.

But there is a catch. Bruce of the future imprisoned Brainiac into the bat-computer and basically rendered him powerless. He discovers some of Brainiac's blueprints, including one for a Kryptonian time machine which be uses to send Terry back in time, but that part of Brainic awakens and stows away on the Bat-plane to the past to merge with it's past self and become even stronger.

It is mentioned that there is a time paradox by the way.

Brainiac ends up possessing Terry's suit, but Terry wins by taking out the power source from the new bat-plane, which in turn turns off Brainiac.

Most misleading cover ever too.

I am not good at tagging so hopefully I got it right.