Alias: Replaced (APO Series #4)

Agent Sydney Bristow has always held her own in the traditional boy's club of espionage. In fact, she's grown comfortable in her well-earned role as respected go-to girl. But with the recent addition of her half-sister, Nadia, dynamics inevitably shift as Sydney finds herself with a new partner, roommate, and -- even if unintentional -- competitor.
APO's mission to retrieve a mysterious biological weapon is compromised, and in the melee Weiss is infected. Driven by concern and guilt, Sydne...