The Shape of the Final Explanation
The Mystery of The Invisible DogThe case moves from a collection of local emergencies to a single criminal plan, while retaining one supernatural question beyond the reach of proof.
increasing
Bearing strength in each event
decreasing
Separate Incidents

Separate Incidents
A crowded sequence
The neighborhood has seen a stolen sculpture, a poisoned resident, an explosive car, and a fire. Each event initially suggests a separate danger.
A connection suspected
Jupiter Jones argues that location and timing link the incidents. The investigation shifts from responding to emergencies toward finding a shared motive.
A Pool-Centered Theory

A Pool-Centered Theory
The object nearby
Jupiter Jones reasons that the Hound must still be close and that residents are being driven away from the pool. The attack sequence appears designed to clear the area.
A theory tested
The boys do not yet know the exact hiding place, but the pool provides a concrete search target. Their case narrows from a neighborhood-wide mystery to a specific space.
The Object Recovered

The Object Recovered
A hypothesis confirmed
Jupiter Jones finds the transparent Hound on the tiled floor. The discovery confirms both the hiding place and the logic behind the attacks.
A new objective
The problem changes from finding the sculpture to identifying its thief. The boys return it to the water to make the criminal reveal himself.
The Hospital Culprit

The Hospital Culprit
A suspect resolved
The failed park handoff sends Jupiter Jones to John Murphy’s hospital room. Murphy’s disguise as a patient cannot withstand the accumulated evidence.
The plan unified
The burglary, attacks, fire, and ransom demand become parts of one scheme. The case’s apparent coincidences resolve into a sequence of choices made by a single offender.
The Unclosed Mystery

The Unclosed Mystery
The criminal account complete
Jupiter Jones explains the motives and mechanics of Murphy’s crimes to Alfred Hitchcock. The main investigation has a satisfying evidentiary conclusion.
A final uncertainty
The phantom priest still resists resolution. The novel ends by distinguishing a solved crime from a mystery that remains genuinely open.
After the poisoning and car explosion
After the apartment fire
The afternoon before the ransom deadline
Late afternoon on the ransom day
Mid-January at Alfred Hitchcock’s office