Timeline

Question

What is the book’s chronology, and where does the text actually pin a date?

Evidence

When	Event	Chapter
The previous winter, before dawn	Paul Lowell, dressed as Spider-Man, is thrown from the platform above London Wall by a man in a Batman costume; he survives. C09 dates this to “back in the winter”.	C00, C09
A heatwave, months later — evening	The narrator tours Slough House at dusk; Catherine Standish meets Sean Donovan on Aldersgate Street and is seized in front of the tube. Lamb dismisses two missed calls.	C01
Next morning	Catherine’s absence registers. River meets the man from the bridge and is given roughly eighty minutes; Louisa searches the flat in St John’s Wood.	C02–C03
That day	River bluffs into Regent’s Park and is caught in Records; Duffy interrogates him; Lamb asks Taverner for him back. Monteith is killed by Donovan; Judd lunches alone at Anna Livia Plurabelle’s.	C04–C06
The following morning	Tearney tells Lamb in St Giles Cripplegate that Slough House closes that morning; Monteith’s body is found; the new demand arrives.	C07
Same day	River is released; Lamb reopens the house and sets a five o’clock deadline.	C08
That evening	Judd and Taverner meet in a square off Praed Street; the slow horses report; Lamb sacks Marcus and Shirley; Donovan calls on Catherine’s phone.	C09
The next day	The archive operation: the bunker, Douglas, the ambush, the farmhouse rescue, Duffy’s killings. Catherine has been held “a full day” by this point.	C10–C12
That night	The firefight and the escape; Traynor killed, Donovan wounded, Marcus taken, Duffy disabled.	C13–C15
Afterwards	Taverner lays out the aftermath on a bench near Paddington; the folder proves to be a decoy; a storm breaks over Aldersgate Street.	C16

Reading

The present-tense action is short — roughly four or five days — and the book does not date it. Three anchors are explicit:

1. The prologue is a different season. Fog, damp and a winter morning in C00; a heatwave from C01 onward. C09 confirms the attack happened “back in the winter”, so the gap between the prologue and the main action is months, not days.
2. The records moved “last month.” Tearney confirms the Virgil-level transfer in C03 and River gives the same figure to Douglas in C11, which quietly establishes that the archive was relocated before the plot began — the tiger team is exploiting a recent administrative change, not an old one.
3. Donovan is “thirteen months” out of prison (C01), having served five years for the crash that killed Alison Dunn. That fixes the Dunn affair to roughly six years before the present.

The book’s compression is the point: a kidnapping, a Service audit, a Home Secretary’s coup and a bunker assault all happen inside a working week, and the heat is used as a physical fact — everybody is tired, sticky and short-tempered, which is how the Park gets away with so much.

Confidence

High on sequence and on the four-to-five-day span (the day changes are explicit: “next morning”, “that evening”, “a full day”). Medium on the total duration — the text never counts the days, and C06 could fall on either the first or second day after the kidnapping. High that the prologue precedes the action by months, from the weather and C09’s “back in the winter”.