Warning! Spoilers ahead for Dark Nights Death Metal: Speed Metal #1
It's a race like none other in Dark Nights: Death Metal. In the Flash Family tie-in entitled Speed Metal, The Batman Who Laughs is after Wally West and his Anti-Crisis Energy he received from Doctor Manhattan and the Mobius Chair. While Wally had been using the power to repair the timeline, the Batman Who Laughs no doubt desires its power for much darker purposes. Thankfully, Wally has his Family at his side to back him up against a legion of Black Flashes.
In Dark Nights Death Metal, Perpetua and the Batman Who Laughs have thrust the Multiverse into darkness, reshaping it into their own image, creating twisted realms, and forcing DC's heroes into torment and more desperation than they've perhaps ever felt before. However, the Batman Who Laughs has agendas of his own, placing his own brain into the body of a Batman who received the same powers as Doctor Manhattan, granting him an insane level of powers which turns him into the Darkest Knight. Even so, he still wants more power. Wally's power.
At the beginning of Speed Metal, from Joshua Williamson and Eddy Barrows, the Darkest Knight is speeding after Barry Allen, Jay Garrick, and Wally West. They are soon joined by Kid Flash, and the four of them have no plan but to keep running. Eventually, the Darkest Knight releases his legion on Black Flashes from across the Dark Multiverse, and it's almost too much to bear. In a risky move, Wally uses the Speed Force Formula developed by Johnny Quick to buy them some time, giving them a moment to assess and breathe, though it does accelerate the Speed Force's burnout. Eventually, Wally comes up with a plan, though it involves running through the Black Flash hordes. If they can reach the Mobius Chair and get it to Wonder Woman and the rest of the heroes, the Chair can help turn the tide. While Barry initially resists the idea, the two speedsters eventually reconcile their differences, and Barry determines to trust in Wally, letting him lead the way.
While the race through the horde works well, it does result in Wally being the only one to make it to the finish line, getting to the chair before the Darkest Knight could destroy it. Thankfully, when Wally got to the Chair, it transported him back into the Speed Force, but also pulled in the rest of the Flash Family with him to safety.
Even though he's back together again with his wife, kids, and the rest of the Flash Family, Wally decides that they can't just stay protected in the Speed Force forever. They have to use the last of his anti-crisis energy and the Chair to help restore the Multiverse with the Justice League. At the end of Speed Metal, Wally leads the way with Barry, Jay, and the Mobius Chair, ready for the next chapter of Dark Nights: Death Metal.