Czech indefinite pronouns like 'nekdo' (someone) (unlike indefinite nouns like 'penize' (money)) cannot be pronounced in their base (postverbal) position unless they are interpreted as narrowly focused. Broad focus (focus on the whole verb phrase) is only facilitated with indefinite pronouns in a derived (preverbal) position. The analysis in this paper makes use of the fact that Czech indefinite pronouns are morphologically related to wh-words. It is argued that wh-words in Czech denote lambda-operators, which are viewed as functions from truth values to predicates. It follows that wh-words (and indefinite pronouns) must be interpreted in the sister-node of an expression denoting a truth value and therefore can never be interpreted in their base position. Finally, it is suggested how the analysis could be used to account for the behavior of the indefinite pronoun 'kdokoliv' (anyone), which is (under certain conditions) interpreted as a free choice item in a narrow focus (postverbal) position and as a negative polarity item in a broad focus (preverbal) position.