The Secret Service Cover
Partners in CrimeThis flow follows the agency's dual life as a public detective business and a covert channel for exposing foreign agents.
increasing
Bearing strength in each event
decreasing
Carter's Proposal

Carter's Proposal
A Departmental Need
Mr. Carter offers Tommy a leave of absence and a ready-made detective agency. Its former manager has been detained, leaving a useful identity available.
A Hidden Purpose
The public business will attract clients while helping the Secret Service monitor Russian correspondence and suspicious visitors. Tuppence sees adventure where Tommy sees operational risk.
The Russian Letter

The Russian Letter
A Coded Contact
A blue Russian stamp letter arrives under the name of a supposed ham merchant seeking his wife. Carter's instructions make the stamp itself a key to the hidden message.
A Watched Office
The letter links the agency's everyday post to an international network. The Beresfords must preserve evidence while avoiding premature exposure.
A False Detective

A False Detective
The Bower Story
A visitor calling himself Dr. Charles Bower describes stolen poison notes and invites Tommy to a nighttime meeting. Tuppence recognizes the story as an implausible lure.
The Countermove
Inspector Dymchurch appears to offer official help, but he is part of the same trap. His betrayal reveals that the enemy understands the agency's cover.
The Office Trap

The Office Trap
Tommy Captured
Tommy is bound in his own office while the gang searches for the letter. The impostor threatens him and demands that Tuppence bring the document.
Tuppence's Counterplay
She has already sent the original onward and arrives with an empty envelope. Inspector Marriot's team uses the meeting to arrest the conspirators.
No. 16 Arrives

No. 16 Arrives
Recognition by Password
A disguised agent enters as Prince Vladiroffsky and tests Tommy with the established phrases. Tommy answers correctly, buying the department a chance to follow him.
The Cost of Deception
The spy anticipates surveillance, escapes in disguise, and takes Tuppence. The hidden operation becomes a personal emergency rather than merely a professional contest.
Opening chapter
After the office begins operating
That same afternoon
That evening
Final case, near the ending