"Derek," Barry breathes, his throat thick when Derek puts it in those terms. Even if he hadn't, Barry can hear the agony in his voice. Derek had been upset when Oliver left, but this is something else, something even deeper, and Barry feels like his own heart is breaking.

"I'm so sorry," he says, holding him tightly, pushing one hand over Derek's heart as if he could hold it together himself. "I'm so sorry, what can I do?"