The Mission

Percy and Annabeth were on a date in New Rome, you know, eating ice cream and talking about Queen Dirt Face, the usual stuff. But then Annabeth sees something. A streak of red and yellow appears out of nowhere, then disappears without a trace. That's when Percy finds out that that streak was a person... 17 years old, like him, and his name was Kid Flash.
Meanwhile, an evil force is stirring, waiting for the time to make its move...
(This is in between the 1st and 2nd Season of Young Justice, and between the Heroes of Olympus and Oracles of Apollo)