A British agent mysteriously murdered on Lake Konstanz in Germany. Keith Martel, his replacement, must move swiftly. Aided by Claire Hofer.

The neo-Nazi DELTA organization are conspiring ruthlessly. Someone else is conspiring equally savagely. Double Jeopardy.

A nightmare bloodbath in Zurich. A sudden attempt on Martel's life. And close to midnight on 2nd June, the Summit Express moves east, taking the four top Western leaders to meet their Soviet counterparts in Vienna.

One of them is targeted. Which one is Martel's problem.

And for the first time - Tweed appears.