Skids and his brother were part of a taskforce deployed in Shanghai to root out Decepticon activity. Even though they didn't understand everything the silly biker ladies were saying, Skids and Mudflap let Arcee escort them both to their stolen ship, past hordes of drones, Flatline and Thundercracker himself before the outpost self-destructed. They probably would've spent the rest of their days locked up and experimented on if a recently upgraded Arcee had not sprung them from their cell. There, unscrupulous Decepticon medic Flatline attempted to forcibly reprogram them into loyal Decepticon soldiers, but all he ended up doing was knocking out a good chunk of their intellect and reasoning skills.
Some time after hearing Optimus Prime's rallying call but before making it to Skids, and Mudflap were kidnapped by Thundercracker and taken to an unspecified Decepticon outpost.
