Colin, an only child, and Nevaeh, the youngest of five, are both reluctantly working at their families' businesses for the summer. At Possession Curation, Colin is tempted to rescue items his ultra-minimalist mother culls from her clients' homes but mostly settles for taking pictures of them, finding beauty in unwanted objects. Nevaeh's father loves being the Junk King, but Neveah would prefer a little less mess in her life. Colin finds a box of letters from the 1970s in an attic and becomes caught up in the story of former friends Rosemary and Toby. A hunch about where he might find the other half of the correspondence brings him into Nevaeh's path, and the two become friends while searching for Rosemary and Toby and trying to figure out what drove them apart. When a brewing conflict between their parents intensifies, Colin and Nevaeh end up solving the mystery of the broken friendship as well as that of an empty storage unit, allowing the adults to resolve longtime misunderstandings. Haddix packs a lot into a fast-paced novel, and she does so while keeping the focus on the plot. Issues of class, equality, and self-determination are touched on in a slightly convoluted but ultimately unexpected and satisfyingly resolved mystery. Sarah Rettger

In the small town of Groveview, Ohio, two 12-year-olds solve a mystery.Colin's and Nevaeh's families approach the business of material possessions from opposite directions: Colin's single mom, who's so minimalist his friends think the family is poor, runs Possession Curation, a company dedicated to helping people declutter their lives. Nevaeh comes from a large, loving family; her father, the self-proclaimed Junk King, never met scrap he wouldn't keep until he could sell it. One day, Colin finds a box of letters dated 1973-77 and written by someone named Toby to a certain Rosemary hidden in his mother's client's attic. In the first letter in the shoebox, Toby pleads with Rosemary not to hate him. Meanwhile, Nevaeh helps her dad open a long-locked self-storage unit and finds it empty when it should have been full of antiques. Gradually, in third-person narratives that alternate between the two White tweens, Colin and Nevaeh meet, become friends, realize that their families share a history, and solve the entwining mystery of their finds. Haddix writes with her usual smooth skill in this series opener, weaving in an interesting theme about possessions and what they mean to different people. Nevaeh longs for Colin's clean home, while Colin finds persistent beauty in the things his mother discards. Though the mystery they solve relies heavily on coincidence, it's credible, as are all of Colin's and Nevaeh's actions. The characters are real and inviting, and the emotions ring true.Fast-paced and enjoyable. (author's note) (Mystery. 8-12)

Two white 12-year-olds from rival small-town Ohio junk-removal families bond over a historical mystery in this accomplished series starter by Haddix (The School for Whatnots). Though introverted Colin Creedmont privately finds beauty in castoff objects, he dreads spending the summer helping his single mom, owner of Marie Kondo–esque business Possession Curation, clean out houses. Meanwhile, self-possessed Nevaeh Greevey, youngest child of the competing Junk King, longs for pristine possessions, and is similarly unexcited to join the family business. Colin’s attic discovery of a shoebox full of letters written in the 1970s leads him to Nevaeh, and the duo bond while searching for the corresponding letters. Reading the missives offers the pair a tantalizing glimpse at a previous era, and as Colin and Nevaeh eagerly research period references such as the Equal Rights Amendment and Happy Days, they resolve to track down the letters’ authors, while Nevaeh surreptitiously puzzles through a crime that could implicate Colin’s mother. Brief third-person chapters alternate between the duo’s experiences, building momentum through a gently feminist undercurrent while conferring character depth via the tweens’ affection for the letter writers and their own opposing views on objects from the past. An author’s note further contextualizes the 1970s details discussed. Ages 8–12. Agent: Tracey Adams, Adams Literary. (Sept.)