Young Justice: Outsiders episode 23, "Terminus," sees the original members of the Justice League's junior team sharing a dream of their fallen friend, Wally West. The first Kid Flash famous sacrificed himself to save the world in Young Justice's season 2 finale and the short sequence seemed to briefly tease his return from the dead, which many fans have predicted occurring sometime in season 3.
The main plot of "Terminus" centers around a mission to rescue the hero Halo from the clutches of Granny Goodness. Armed with a set of coordinates to Granny's space-station base, the Orphanage, a rescue team is assembled made up of Geo-Force, Terra, Forager, Aquaman, Ms. Martian, Superboy, Tigress and Nightwing. While this sort of mission would normally only involve members of the Team (the covert superhero group maintained by the Justice League), many of the heroes had a personal stake in the mission. For instance, Geo-Force was romantically involved with Halo, while Tigress, Terra and Forager had come to view Halo as a foster sibling.
Ms. Martian led the mission as the leader of the Team, with her fiance Superboy coming to offer his support to her. Finally, Aquaman came along because of a promise he had made to Nightwing's girlfriend, Oracle, to keep an eye on a still ailing Dick Grayson, who insisted that he was feeling fine and back in fighting shape, despite a slight fever. Dick's assessment of his health was far too generous, however, and he was soon sweating and breathing heavily when the team met resistance in the form of a Parademon platoon. After one laser blast left Nightwing stunned and stuck under a pile of crates, he was surprised when a familiar yellow-clad figure offered him a helping hand in getting free of the debris and Kid Flash entered the fight.
It was immediately clear that something strange was going on to keen-eyed viewers. The first clue was that Aquaman and Tigress were back in their original costumes from Young Justice season 1, back when they were still Aqualad and Artemis, as Kid Flash ran around the field of battle. Another clue came when Kid Flash referred to Artemis as "the new girl" and spoke of his "fantasy first date" with Ms. Martian. Kid Flash got over his crush on Ms. Martian and became romantically involved with Artemis at the end of Young Justice season 1. The final clue came when Kid Flash went back to Nightwing to find a visibly younger Dick Grayson wearing his original Robin costume.
The battle sequence that followed acted as a wonderful visual tribute to the first season of Young Justice, yet one that advanced the present story. For the team, it strengthened their resolve for the fight to come; the memory of their fallen friend reminded them of what they were fighting for and led Tigress to declare that "Wally's always fighting at our side and he always will be." For the viewers, the sequence was a reminder of just how richly these young heroes have been developed over the course of the past three seasons and how, heading into its grand finale, Young Justice: Outsiders can still find ways to touch their hearts and surprise us.