"Kensington Cozies"--Spine.

Series enumeration taken from Fantasticfiction.com.

"April Claus is looking forward to relaxing with her hubby, Nick (aka THE Santa Claus), in the week between Christmas and New Year's Eve. But just after Santa departs for his deliveries, an elf pulls into Santaland with three people he found lost in the frozen wilderness. The survivors of a scientific expedition are injured, but their presence endangers the future of Santaland. So, while the strangers recuperate at the infirmary, April convinces Christmastown to pull off its grandest, most impossible, most magical feat yet... pretend to be normal! Posing as a touristy, albeit Christmas-centric, artic town, the elves cover their ears, snowmen take a vow of silence, and the reindeer keep their hooves on the ground. But as New Year's Eve draws closer, hiding their true selves becomes harder to do, especially when one of the uninvited guests dies under highly suspicious circumstances. With a murderer in their midst, April sets out to find the uncorked culprit before any auld acquaintances should be forgot...or worse."--Back cover.