Shellshock 2: Blood Trails is a first-person shooter video game developed by Rebellion Developments and published by Eidos Interactive for the PlayStation 3, Xbox 360 and Microsoft Windows. It is the sequel to Shellshock: Nam '67, developed by Guerrilla Games and published by Eidos in 2004. It was released in February 2009.
Shellshock 2: Blood Trails is a first-person shooter set during the Vietnam War. The plot revolves around a special operations team led by Sergeant Caleb "Cal" Walker, who vanished after being sent into the jungles of Cambodia to retrieve a mysterious cargo known as WhiteKnight, which was lost after a U.S. transport plane was shot down by a NVAF jet. Cal lost his men to the earliest victims of Whiteknight, the downed U.S. plane crew. Cal was infected with the virus that he meant to secure.
One month after the event, Cal comes out of the jungle alone, only to be captured and brought to a U.S. base in the Pleiku Highlands. Cal's newly drafted brother, Private Nathaniel "Nate" Walker was brought by Sgt. Jack Griffin to the base in order to extract info regarding WhiteKnight from his deranged brother. Unfortunately, Cal was able to escape after killing some soldiers during a VC attack on Pleiku. The joint VC/NVA attack was orchestrated by Nguyen Van Trang, a VC officer sent to capture Cal.
Nate, with help of Griffin, and GIs that he met along the way, must hunt down Cal, moving from Pleiku to an old temple in Cambodia. Nate is also tasked to stop Nguyen Trang and his comrades from capturing Cal. Nate, through the course of his journey, combats those infected with WhiteKnight, the VC, and NVA.
Source: Wikipedia, "Shellshock 2: Blood Trails", available under the CC-BY-SA License.