The Night of Morningstar is the title of the eleventh book chronicling the adventures of crime lord-turned-secret agent Modesty Blaise.
The novel was first published in 1982 and was written by Peter O'Donnell, who had created the character for a comic strip in the early 1960s.
"The Watchmen" is an international terrorist organisation that has sprung out of nowhere and is making major assaults, for example killing the entire Turkish Embassy staff in Madrid, wrecking a French nuclear power plant, and blowing up a dam in Utah.
She and Ben are held at gun point on a small fishing boat in San Francisco Bay as The Watchmen make final preparations to destroy the Golden Gate Bridge.
This has to be prevented, of course, but before Modesty and Willie can get a warning out they are captured by The Watchmen and imprisoned and drugged such that they can not possibly escape.