Shiwei Chen is a Chinese spy. He is running a scheme to financially destabilise the US economy through gambling profits. He arranges to ferry a number of "high roller" poker players back and forth to move money into the US. He is exposed when he is photographed by Eleanor Wish at an illegal game, chastising one of his players for arranging an additional night of play when they should have returned to China on a pre-arranged flight.
He discovers that he has been identified and arranges for Eleanor to be murdered in a drive by shooting. Eleanor's ex-husband Harry Bosch investigates the killing and finds out through her FBI connection that Chen is a Chinese diplomat. He gives Chen his card and presses him about the killing.
Chen arranges for his unidentified subordinate who carried out Eleanor's murder, to be killed and left for the FBI to find in the trunk of a car with Bosch's card between his teeth.
The FBI allow Chen to flee the country to avoid an international incident, to Bosch's chagrin.