The nature and the typological validity of the categories ‘realis’ and ‘irrealis’ has been a matter of intensive debate. In this paper we analyse the realis/irrealis dichotomy in Tundra Yukaghir (isolate, north-eastern Siberia), and show that in this language realis is associated with a meaningful contribution, namely, existential quantification over events. This contribution must be expressed overtly by a combination of syntactic and prosodic means. Irrealis is the default category: the clause is interpreted as irrealis in the absence of the marker of realis. This implies that the relevant typological question may turn out to be the semantics of realis, rather than irrealis. We further argue that the Tundra Yukaghir realis is a hybrid category composed of elements from different domains (information structure, lexical semantics, and quantification) unified at the level of interpretation via pragmatic enrichment. The concept of notional mood must therefore be expanded to include moods which come about in interpretation and do not constitute a discrete denotation.