This paper argues that Algonquian first person exclusive plural contains a double-person feature, namely, first person and third person, given the person hierarchy (PH) and the plural hierarchy (PLH) exhibited in the person-number agreement. There are two issues encompassing the PH and the PLH: first, the PLH (1p > 2p) contradicts the PH (2 > 1); second, the PH is valid in the main clause inflection but not in the subordinated clause inflection. I maintain that the PH is an entailment of person feature specifications (cf. Béjar & Rezac 2009; McGinnis 2008). The first issue can be resolved by the double-person feature, as [1p] is more specified for the additional π-feature than [2p] for the simple [pl] feature. The second issue can be captured by the Activity Condition (AC) motivated by the less articulated probe. The subordinated clause inflection applies the AC, and thus only targets the active goal. Contrarily, the more articulated probe in the main clause inflection is attracted to target the better-matched goal, and therefore the AC can be relaxed. This paper reveals a deep connection to person-number agreement in two inflectional systems in Algonquian: the probes can be different, but the features remain invariant.