"Why Was the Fireplace Burning?" is the seventh case arc in "The Kindaichi Case Files R" series of The Kindaichi Case Files.
Itsuki takes Kindaichi and Miyuki along to a lakeside cabin area in a more remote section within Tokyo, both as precaution for the upcoming inheritance dispute after a company owner who knew and helped Itsuki in the past passed away just days ago and the deceased owner's lover invited Itsuki over as a neutral party and to investigate a threatening letter the owner's lover received. The precaution ends up paying off because one of the potential candidates for the inheritance dies later that night.
Tropes include:
- All Just a Dream: On the night after their arrival, Kindaichi has a hard time falling asleep, Miyuki drops by his cottage in lingerie and claims she can't sleep alone, resulting in the two of them starting to get intimate... before the next panel shows Kindaichi holding his pillow in a tight embrace, puckering his lips, and talking in his sleep, which means Miyuki's "intimacy" with him was only in his dreams all along.
- Compliment Backfire: When the participants for the inheritance dispute question the presence of Kindaichi and Miyuki, Itsuki introduces Kindaichi as Kosuke Kindaichi's grandson, but his choice of words are less than ideal for Kindaichi.Itsuki: He might look dim and moronic, but he's actually the grandson of the famous detective, Kosuke Kindaichi!
Kindaichi: *thinking internally* Moronic? - Conveniently an Orphan: As Kindaichi reveals to the culprit near the end of the case arc, the victim grew up as an orphan due to her mother dying when she was young and her father having made no contact with her.
- Family Relationship Switcheroo: The deceased owner's "lover" turns out to be his biological daughter, and her mother was the owner's actual lover. According to her confession, everyone started calling her his "lover" after her mother's passing.
- Never Suicide: The victim's death by Slashed Throat is arranged to look like a suicide, but Itsuki suspects it's actually a murder, which Kindaichi soon confirms as well.
- Slashed Throat: The victim dies from a knife cut across the throat.
- Widow's Weeds: A plot-relevant example. According to Kindaichi during the Summation Gathering session, the culprit is the one wearing dark clothing, in order to conceal the soot getting attached to the clothes while pretending to be a mourning widow.
