From the publishers website:
The TARDIS lands in 1997 Jerusalem. Civil unrest and political and religious tension is on the rise in the city despite attempts to make peace in the region. Only the United Nations peacekeeping force has kept the area from exploding into violence. Archaeologists uncover an alien artifact in the city ruins and every side wants to claim it for themselves. The United Nations Intelligence Taskforce (UNIT) is called in to investigate and to keep the peace. The TARDIS crew must assist UNIT in investigating the alien object and tracing its origins, while also preventing needless violence from erupting.