Complex sentence: A disillusioned US human rights activist James Rhodes (played by actor Jeff Daniels) arrives in Tijuana to help oversee local union elections only to become embroiled in a mass murder at what appears to be a drug runners' tunnel on the Tijuana/San Diego border.
Split into simpler sentences: A disillusioned US human rights activist James Rhodes (played by actor Jeff Daniels) arrives in Tijuana to help oversee local union elections. While there, he becomes embroiled in a mass murder at what appears to be a drug runners' tunnel on the Tijuana/San Diego border.