Sleuth Kings

What's in the box: A physical case file of clues, evidence and puzzles for one stand-alone mystery, plus either a reward (Master) or an epilogue letter (Rookie) once you solve it.

Sleuth Kings sends a new, stand-alone mystery each month as a physical case file packed with clues, evidence and puzzles. What sets it apart is the email element: you correspond with a fictional lead detective, Sullivan King, as you work through the case, and submit your final answer to him to learn whether you cracked it. That back-and-forth makes it feel more interactive than a box you simply open and solve on your own. There are two tiers. Master Detective is aimed at experienced puzzle solvers, takes about two to three hours, and includes a reward for solving the case. Rookie Detective is pitched at beginners, takes about an hour, and ends with an epilogue letter. Each case suits one to four players, so it works for a solo evening, a couple or a small group. Because every mystery stands alone, you can join in any month, and an archive of past cases lets you catch up on older stories. A free mystery is offered so you can try the format first. The site does not list prices up front, and subscriptions have a monthly cutoff and can sell out, so you may have to wait for the next case. Despite the true crime label, these are puzzle mysteries built around fictional cases rather than real ones.