Sam & Klaus
Even if Sam hadn't promised to find Klaus he would have. There were a lot of people around, a lot of people to mingle and talk with, and no doubt a pretty high number of them would say they were friends. Klaus, though, was someone he ranked fairly highly back, and with Bucky having just gone and replaced himself a party possibly wasn't the best environment to try to be sober in. He'd gotten a couple of glasses of juice and soda and was working his way around the room, scanning faces as he searched and amiably waving off anyone who tried to stop him to talk.