Dark Flash
The Black Flash
During a fight with the Black Flash, who had apparently claimed the life of Linda, Wally saved her from the Speed Force. He proposed to her and they were almost married shortly thereafter, but she then disappeared off the face of the Earth, and no one, not even Wally, remembered her.
Wally then got caught up in an adventure spanning through different eras. Malcolm Thawne, Barry Allen's twin brother, reappeared, beginning the Allen-Thawne feud. Barry's death during the Crisis on Infinite Earths appeared to have cheated Malcolm out of his dreams of revenge on his brother. Instead, Malcolm focused on Allen's descendants traveling through time in a bid to exterminate them, starting with Wally West. Under the identity of Cobalt Blue, Malcolm ignited a family feud that endured for a millennium.
The feud came to a head in the late 30th Century, where Barry Allen was living with his wife Iris. Wally West arrived to try and protect his uncle. Flashes of all eras between the 20th and 30th centuries arrived soon after, all under the control of Thawne's spirit because they all were carrying a shard of the original Cobalt Blue gem. In the end, Wally West ended the menace of Cobalt Blue by running so fast that he skirted the edge of the Speed Force. Its power poured into the gem, and Thawne's spirit (and the gem itself) overloaded from the excess energy. Wally then vanished into the Speed Force. At that same moment, a new, mysterious Flash appeared in Keystone City.
Linda's disappearance was caused by a mysterious man who had a deep hatred for the Flash; he abducted her and kept her imprisoned within Limbo. This was also the reason behind why everyone on Earth had forgotten about her--Linda was taken from a time prior to her originally meeting Wally. Linda escaped from his prison and landed in an alternate Keystone City, where she encountered who she thought was Wally, until she noticed three distinct things: Keystone City's police were after Wally and called him "Walter"; Wally seemed to be mentally unbalanced; and this Wally's eyes were blue, not green. Linda next encountered this world's Pied Piper , who told her to run from Wally because he was dangerous.
Linda ran toward the Flash Museum, where she found a memorial statue dedicated to her dimensional counterpart, who sacrificed her life to save Keystone City from the villain Kobra. After again encountering Walter at a cemetery, Wally, following his link to Linda, emerged from the Speed Force. A battle ensued between Wally and Walter, where they were evenly matched. However, Walter came back with a vengeance, pinning Wally to a wall with a vibrationally-charged rebar. Wally tried to explain to Walter that he and Linda were from a parallel world; he also explained that although they share the same memories, Wally could never turn into the man Walter has become. That statement set off Walter's anger once again, starting another fight with Wally.
Walter then let loose with the fact that after his Linda's death, he sought out Savitar, and after tricking him into teaching Walter every trick and skill he knew, killed him. After Walter's revelation, Abra Kadabra appeared, trapping both Wally and Walter. Kadabra explained that he tried to break the bond that draws Wally back to this dimension by casting a spell to make everyone forget that Linda existed and hold her outside of time, but she escaped, landing in that alternate Keystone and drew Wally to her once again. To defeat Kadabra, Wally temporarily merged his physical essence with Walter's, gaining greater speed and learning a few new skills; from this merging, Walter also finally came to terms with not being able to save his Linda from death.
Kadabra, however, faked his defeat at their hands and seemingly discorporated Wally and Linda's essences; in actuality, they ended up traversing through countless alternate dimensions, nearly losing their minds until they found their home dimension, thanks to Bart (he was actually born outside of time, rendering him immune to chronal alterations). Wally and Linda finally made it back to their Keystone City; however, Linda was still forgotten from everyone's minds. Wally then sought out Jay Garrick, told him of his plans to rescue Linda, and set off for the Flash Museum, where he donned a Reverse-Flash costume and "allied" himself with Abra Kadabra and Replicant. Wally then kidnapped Jay Garrick, Bart Allen, and Jesse Quick and took them to Kadabra's abandoned theater hideout, where as Professor Zoom, he taunted Kadabra into reversing the spell he cast on Linda, bringing her back in full, to everyone's memory; Professor Zoom then pulled back his cowl, revealing himself as none other than Wally West. The final battle between Wally, Walter, and Abra Kadabra ensued. Kadabra preparing a spell to wipe the memories of the Flash legacy from the world's minds forever. On Linda's suggestion, Wally, Walter, Jay, Max, and Bart used mirrors to block and reflect Kadabra's spell back at him, rendering Kadabra himself with amnesia. A short while later, Linda gave birth to twins, Jai and Iris.