EPISODE 17 – A Clean Conscience
The team attempts to recover a bio-weapon capable of wiping out an entire ecosystem from the Beograd Faction. Dixon goes undercover to infiltrate the terrorist group. Meanwhile, as Jack deals with the results of his actions at the nuclear facility. Sydney and Nadia are given startling information about Elena Derevko.

EPISODE 18 – Mirage
With Dixon still embedded in the terrorist group, the APO team follows him to Vienna to steal back the Hydrosek. A trusted friend betrays Nadia and the rest of the APO team. Jack's condition worsens, causing convulsions and hallucinations. To make matters worse, the only man who knows the location of the doctor who can cure Jack...is Jack.

EPISODE 19 – In Dreams...
The APO team sets a trap in Paris that manages to snare the Sloane imposter. After Jack uncovers the origin of the Sloane clone, Marshall devises a way to shock him back into his own identity – a technique that poses a potential danger to the real Sloane.

EPISODE 20 – The Descent
The APO team belatedly discovers that Elena Derevko has been in their midst for some time and has managed to get away before being discovered. She must be found before she can assemble the Rambaldi pieces. A flashback reveals Nadia's importance to the final prophecy. And a critically wounded Dixon has astonishing news for Sydney and Nadia.