Captain Hastings

The Unexpected Guest

Visits Poirot and inadvertently triggers the stranger's revelation by mentioning 'The Mystery of the Big Four'; accompanies Poirot partway before the abrupt departure.

II: The Man from the Asylum

Accompanies Poirot back to London; assists in the investigation; observes the clues.

We Hear More About Li Chang Yen

Hopes the fake asylum attendant will return; accompanies Poirot to visit Mr. Ingles; protests the idea of a Chinaman controlling Russia.

IV: The Importance of a Leg of Mutton

Accompanies Poirot, offers imaginative hypotheses, and observes the investigation.

V: Disappearance of a Scientist

Narrates the chapter, expresses frustration with Poirot's passive approach, and accompanies him to visit Mrs. Halliday.

The Woman on the Stairs

Accompanies Poirot to Paris, observes the woman on the stairs, and is nearly killed by a falling tree.

VII: The Radium Thieves

Eager for action, struggles with the visitor, and is crestfallen when the visitor escapes.

In the House of the Enemy

Under the alias Major Neville, Hastings infiltrates Ryland's household as a secretary, discovers the coded letter, and arranges a meeting with Poirot.

IX: The Yellow Jasmine Mystery

Hastings is frustrated with the lack of progress against the Big Four and accompanies Poirot to Market Handford. He narrates the details of the Paynter case.

X: We Investigate at Croftlands

Accompanies Poirot to Croftlands, observes the investigation, and comments on the case.

XI: A Chess Problem

Narrates the chapter; discusses the case with Poirot and retrieves a chess book for him.

The Baited Trap

Receives news of his wife's kidnapping and is lured into a trap by the Big Four, leaving a clue for Poirot.

The Mouse Walks In

Captured and coerced into writing a decoy letter; later rescued by Poirot.

XIV: The Peroxide Blonde

Narrates the chapter, assists Poirot, and is disappointed by the lack of documents found.

XV: The Terrible Catastrophe

Narrates the chapter; survives the bomb and vows to carry on Poirot's mission.

The Dying Chinaman

Grieving Poirot's death, Hastings is determined to avenge him and hunt down the Big Four, ignoring advice to return to South America.

Number Four Wins a Trick

Narrates the chapter, chafing at the forced inactivity. He recounts the dying message from Ingles's servant and insists on accompanying Poirot to the Tyrol.

In the Felsenlabyrynth

Narrates the chapter; captured and brought to the Big Four's lair, later rescued after the explosion.