This issue is another in a long line of one of Captain America's staple features: characters flashing back to escapades in the war years.  In this case, the theme is Bucky's various birthdays.  His 16th, when he crashed a base jeep and got thrown in jail, before being told he would be sent to the UK to train with the SAS for a few months (and, soon after returning, was made Cap's partner); his 20th, just weeks before his and Steve's war ended in battle with Zemo (in which he and Steve went to a bar after Steve speechified a Nazi into telling them where Zemo was), and this one, his 18th, in 1943, when he, Steve, Jim "Human Torch" Hammond and Toro were hanging out in Nazi-occupied Poland.  Toro secretly ordered a cake made, and wants to have a party; Steve and Jim both say no, because they don't want to blow their cover, but Toro says he already ordered the cake, so there's no going back.  Bucky enters and asks what's going on.



The matron's a Nazi sympathizer ("I didn't know!" protests Toro), but Master Man and Warrior Woman bust in.



The present-day story is Bucky fighting some members of the Watchdogs, who idolized Steve and are out to kill the pretender (and blow up quite a bit of New York City in the process).  He wins, obviously, and returns home to get some sleep, grousing that Luke Cage better not have used all the hot water again.



He's a sprightly 84, Clint.

And, really, everybody but Peter and Logan is now living rent-free at his house, so the least you could do would be to throw him a party.



Careful, Natasha; you can't be less than 75 yourself.