Kevin Henson was the ex-boyfriend of Melanie Davidson, who later became Melanie Cavanagh, and later still a corpse. Her body is the starting point for "A Chill Goes Through Her Veins", in the course of which Beckett and Castle discover, from Charles Wyler, that Melanie would sometimes need a break from her marriage to Sam, and would hook back up with Kevin for a short while, before returning to the bosom of her family. Kevin, it turns out, was in rehab, trying to make himself the kind of man who could give Melanie what she deserved, when she disappeared, and the duo have to look elsewhere for their killer.