"Serum," James gritted out between clenched teeth. "I can't... it's not..." It felt like he was gasping for air, weak and dizzy and completely lost in his own body. Nothing felt like it should, he was suddenly freezing and aching with pain.

The serum was gone, the effects vanishing like they'd never been. Just like his arm had. "It's gone."

Bucky had scrambled up to his knees, hissing as his bloody feet scraped the ground, training the gun back in the direction they'd come. He didn't want any HYDRA sneaking up on them with only Rory paying attention. The mention of the serum drew his attention, however. "What d'ya mean, it's gone? It can wear off?"

In the middle of a battle? The thought was terrifying. If Steve ever reverted to his former self like this... God, he wouldn't survive five minutes.