''Eight Days of Luke'' is a fantasy/mystery novel by Creator/DianaWynneJones. David Allard, forced to spend his school vacation with his despised guardians, accidentally summons a mysterious person who calls himself Luke, in the process freeing him from a magical imprisonment--and then has to protect him from Luke's family, who are after him to give back something he stole.
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!! Tropes featured include:

* AdultsAreUseless: Played straight, then subverted. Most of David's relations are willfully oblivious to the supernatural events playing out under their noses, but Astrid eventually becomes useful, if not downright involved, and of course there is the solicitor down the street...
* BeautyEqualsGoodness: [[spoiler:Astrid is described as "quite pretty" when she's first introduced, in contrast to David's other, ugly relations. By the end of the book, she and David have become very close, she helps David achieve his goals, and David is actively looking forward to living with just her.]]
* BeCarefulWhatYouWishFor: On a shopping trip David wishes something interesting would happen, like a fire. [[spoiler:Luke offers to set one in a nearby building, and David is shocked to realize that he can actually do it and that people are now in danger]].
* BigEater: Luke, who at one point downs multiple ice cream sundaes. [[spoiler:Which makes sense considering his long imprisonment and his mythological exploits.]]
* {{CalvinBall}}: Uncle Bernard and Astrid have daily contests as to who is sicker. David awards points.
* TheCharmer: Luke has David's relatives eating out of the palm of his hand.
* CurtainsMatchTheWindow: Luke has red hair and matching reddish brown eyes.
* DefrostingIceQueen: Astrid dislikes David's family just as much as he does, and when they realize this they start to get along a lot better.
* DirtyCoward: Cousin Ronald chickens out while [[spoiler:running the gauntlet]].
* EvilUncle: It turns out David's uncle and cousin have been stealing money that was rightfully David's and using it for their own illegal purposes.
* GettingCrapPastTheRadar: [[spoiler:In the myths, Loki once accused Frey and Freya of BrotherSisterIncest. They appear disguised as a married couple. In her memoirs, DWJ recalled a close reading editor realizing that Astrid and Thor were having an affair. It almost stopped the book's publication.]]
* FriendshipMoment:
** Astrid remaining with David after the rest of his relatives leave him to what they think is a police interrogation.
** Luke and David when David returns [[spoiler:with the stolen item.]]
* RedIsHeroic: [[spoiler:Thor]]--whom David recognizes only by his red-blond hair--is the most pleasant and trustworthy of the adults David comes in contact with.
* JustWhistle: Luke appears when David strikes a match. [[spoiler:This is used to trap him.]]
* LockedOutOfTheLoop: David can only find what Luke stole if he doesn't know what it is.
* LooseLips: David can only find the stolen item if he doesn't know what he's looking for. Astrid figures it out immediately, and promptly almost spills the beans multiple times.
* MeaningfulName:
** [[spoiler:All the disguised gods -- Luke is Loki, Mr. Chew is Tiw, Mr. Wedding is Woden, and the Frys are Frey and Freya.]]
** David himself--which is probably why he gets on so well with the [[ProudWarriorRaceGuy Norse gods.]]
* PalsWithJesus: Pals with [[spoiler:Loki,]] rather.
* ParentalAbandonment: David's parents are dead and his guardians are spiteful and neglectful.
* RavensAndCrows: Mr. Wedding assigns two to keep an eye on David.
* ReallySevenHundredYearsOld: [[spoiler:Luke appears to be about David's age, but is actually the immortal god Loki.]]
* PlayingWithFire: [[spoiler:Luke.]]
* TheTrickster: Luke.
* UnwittingInstigatorOfDoom: Astrid [[spoiler:accidentally summons Luke into a trap.]]
* WellDoneSonGuy: David and [[spoiler:Sigfried.]]
* WomanScorned: [[spoiler:The ultimate driving force behind the plot. Brunhilde ''wasn't happy'' that Sigfried forgot her or that the gods arranged it that way.]]
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