Not quite over the fatal kiss that killed the highly allergic Dan McAndrew, young Brit Scarlett Wakefield seeks to find closure in this zippy sequel to Kiss Me, Kill Me (2008). Determined to clear her name—and her conscience—Scarlett and her American sidekick, Taylor, set out to find the culprit responsible for lacing the crisps she snacked on with peanut oil. When Scarlett’s search eventually leads to Dan’s ancestral castle in Scotland, she is shocked to discover that Dan had a twin—and that the McAndrews’ family secrets run deep. This precocious investigator learns she may just now be in over her head. Scarlett’s voice, peppered with the usual teen angst and snark, may not be particularly novel, but it nonetheless skillfully sets the tone for this frothy whodunit. Readers willing to take generous plot leaps—for example, when Scarlett melodramatically learns that Dan had a never-before-mentioned twin brother—should be entertained. Filled with duplicitous debutantes, homicidal siblings, all-night parties and lots of designer name-dropping, this sugary mystery may find a similar readership to the Gossip Girl set. (Mystery. YA)