This was wonderful! I really liked the detail, the import of each gesture and glance. I also liked how you took two powerful men and showed their vulnerability. The Harry that put up will sick Severus and was willing to explore their relationship, was so heartbreakingly absent in the second half of the story, until Severus was able to excavate him (hints of Delos, hmmm...?).
"You see, I was spurred on by a disappointment. A friend of mine missed a very important rendezvous." This was achingly beautiful! Severus laying it out there!
Well done, I can hardly wait to find out your identity!