Abstract Referentially vague (or ‘ignorance’) indefinites are known to exhibit apparently conflicting behavior: in the singular, they are referentially vague (Giannakidou and Quer 2013, Alonso-Ovalle and Menéndez-Benito 2010, 2011, 2013), but in the plural they appear to depend on a discourse given set. The phenomenon is typically discussed in the context of Spanish algún/algunos (Gutiérrez-Rexach 2001, 2010, Martí 2008, 2009); but in this paper we offer extensive novel data from the Greek indefinites kapjos/kapjoi exhibiting the same asymmetry between the singular and the plural. The apparent conflict between the two variants, we propose, is just that—apparent: the indefinites remain referentially vague in both uses. Referential vagueness is not at odds with discourse familiarity, and the apparent differences between the singular and the plural follow from NP -ellipsis, the potential topicality of the indefinite, and the way vagueness interacts with plurality.