Now nine months pregnant and on maternity leave, Sydney is surprised when her mother, Irina Derevko, shows up at her front door pretending to be a victim pursued by Prophet Five to get information on the whereabouts of 'The Horizon'. Jack, Sydney and Irina travel to Vancouver to an high-rise office building to steal the Horizon, only to get trapped on the upper floors when Peyton and hit team show up, forcing Jack to do battle with them alone as Sydney finally begins to go into labor with Irina as her labor coach. Elsewhere, while Dixon meets with Renee in Paris for information about The Horizon, back at APO, Rachel, Marshall and Tom agree to cover for Sloan when CIA Director Arthur Devilin arrives to monitor the APO records in the wake of the discovery of Prophet Five mole within the CIA.