Superman the Comic #4

The warring alien races the Volkir and the Zelkot come to Earth in pursuit of Zelkot Iylar who hopes to travel through time and prevent the aliens' war. The Zelkot threaten to destroy Earth if Flash does not help. But after Flash heads off after Iylar, the Volkir convince Superman to stop Iylar. In the 25th century, Superman secretly helps Flash deal with Professor Zoom, before the again pursue Iylar. After a number of stops across time, Superman and Flash catch up to Iylar, stop him from preventing the war, and neutralize the aliens' threat against the Earth in the present.