Casebook

Something has gone missing — or someone has. A handful of suspects, a stack of testimony that doesn't quite line up, and a grid that will tell you the truth if you work it right.

Casebook is a weekly logic-grid mystery: read the clues, cross off what can't be true, confirm what must be, and accuse. Same deduction as a classic logic-grid puzzle, wrapped in a short case you solve as you go.

Every case is solver-verified before it's ever published — a constraint solver builds the solution grid and proves it has exactly one answer before a word of the story is written around it. The logic is never ambiguous and never a guess.

• A brand-new three-case pack every Monday — warm-up, standard, hard

• Every case's solution is unique and machine-verified, never a coin flip

• Clean case-file interface: strike clues as you rule them out, tap grid cells to cycle blank → eliminated → confirmed

• Play in the browser, progress autosaved per case

• Free to play