Watch Young Justice: Future Shock (2018) online

What if Bruce Wayne wasn't the first person Barry Allen traveled to the past to ask for help, what if it was Bart Allen that was tasked with helping prevent Superman's descent into Tyranny. After a visit from the Future Flash, the new Kid Flash must enlist the help of some of his teammates, as well as members of the Justice League, in order to decipher the message given to him by Barry of the Future. All points lead to a trip to the future, but when they arrive, Bart Allen must come face to face with a new truth that may rip his past, present, and future asunder