Created by John Garvin and Richard Ham, Syphon Filter follows protagonist Gabriel "Gabe" Logan who was a secret agent for a black-ops organization known as the Agency. With his partner Lian Xing, Gabe traveled around the world in an effort to stop a deadly virus known as the Syphon Filter virus from spreading. Although they succeeded, Gabe and Lian soon learned that their bosses in the Agency were involved with the terrorist plot and soon became fugitives from their own employers.
In Omega Strain, Gabe was appointed Commander-In-Chief and renamed the Agency to the International Presidential Consulting Agency (IPCA).
Plot Summary (Spoilers)
The plot involves the chase of international terrorist leader Erich Rhoemer and uncovering his bioterrorism plans behind the Syphon Filter virus, with Gabe Logan experiencing subsequent betrayals and conspiracies. It is later revealed that his employer Markinson is secretly working with Rhoemer to obtain Syphon Filter for the Agency. Logan is able to kill Rhoemer and avert World War III.
Taking place right after the original, Gabe leaves Kazakhstan with his CBDC partners after obtaining back-up files pertaining the virus and the Agency's conspiracy. The Agency ends up kidnapping Lian and demands Gabe the data in exchange for his partner. During this ordeal, Lian is infected with the Syphon Filter virus and is up to Gabe to save her with the vaccine. Gabe manages to save and cure Lian but is unable to save his fellow agent Teresa Lipan.
This game is told mostly in flashback during a congressional hearing for the main operatives about their history, the origins of the Syphon Filter virus, and ultimately; stopping Syphon Filter.
Instead of playing as Gabe Logan, the exiled agent from the top secret Agency, players will create their own character, which is a new recruit for the Agency.
The Syphon Filter virus is no more. Now comes a new threat by a paramilitary group known as Red Section. It is up to Gabe and the IPCA to stop its leader, codename Singularity, and to rescue his former Agency partner and lover Addison Hargrove who is involved in the terrorist plot.
Gabe Logan is searching the globe for Lian Xing, who may be in danger, or a double agent. A government official, Robert Cordell, shutting down the IPCA under presidential powers, and Logan in the eyes of an assassin.