This paper is a first systematic study of constructions with the noun 'case'. 'Case'-constructions, which are extremely common in everyday speech, bear on a range of central issues in semantics, such as the semantic role and nature of situations, the semantics of (that-)clauses, the nature and determination of alternatives (alternative semantics), the semantics of conditionals, and the connection of the predicate 'is the case' to truth predicates. This paper develops a unified semantics of 'case'-constructions within a situation-based version of alternative semantics (truthmaker semantics).