Heorot is a short story in The Dresden Files series by Jim Butcher. It is set between White Night and Small Favor. It was originally published in My Big Fat Supernatural Honeymoon, and was included in the anthology Side Jobs.
McAnally calls Harry Dresden at the brewing competition NIGHT OF THE LIVING BREWS at the Loon Island Pub in Wrigleyville, in sight of Wrigley Field. Here, Roger Braddock explains to Mac and Dresden that his newlywed wife, Elizabeth, has gone missing; Herbert Orson Caine joins the discussion, accusing Braddock of stealing his keg of mead, and trying to start a fight, but backs down when he realizes that there is a cop nearby.
Using some of Elizabeth's hair, Dresden starts a tracking spell, but is interrupted by Caine and two associates attacking him. Dresden, however, manages to fend them off with his staff and Mouse's help.
After the fight, Dresden is approached by Ms. Gard, who is hunting the creature, called Grendelkin, that kidnapped Elizabeth. They follow it into Undertown, until they meet malks guarding the creature's lair, which they pass undetected under an illusion. Gard charges the Grendelkin, which proves to be an intelligent and tough opponent capable of countering both Dresden's spells and Gard's skill with weapons. Mouse enters running the fight area, followed by the malks, and distracting the Grendelkin, which is not pleased by the intrusion. During the ensuing melée, Dresden casts an illusion, making the malks go after the Grendelkin, and causing even greater disruption. Dresden, Gard and Mouse use it to get Elizabeth Braddock out of the lair, but are pursued by the malks; Gard manages to block them, by casting a Sunder rune, before they get all out of Undertown.
Back to the Night of Living Brews, Elizabeth and Roger Braddock are reunited, and they all celebrate; Dresden manages to get Ms. Gard to admit she's the valkyrie Sigrun.