From the first mention of Lerner and Lowe, this was a fun story! I really enjoyed the little touches -- the Fly London loafers (black, of course), the reference to Prester John and Samarkand, Snape lecturing Malfoy on guile, just what happened to the banished grey nightshirt, Cockburn's port, and Severus in a luxury flat in Kensington, as well as the nods to canon and their discussions about Draco (and what a clever touch about the potion). Entirely believable that Severus tried to sway Lucius during the first war, and that both refused to rat each other out after they parted ways the first time.
Oh, the irony when Lucius promised anything, but wonderful to see how much more merciful Severus was compared to Dumbledore. And finally, this was a wonderfully mushy line: It had been many years since they embraced each other, but hands remember, lips remember, and hearts remember.