Spider's Web was written at the request of its star, Margaret Lockwood, whose main body of work was in films and who had never appeared in a West End production aside from Peter Pan.

[3] Christie wrote the play during the period of the final rehearsals for Witness for the Prosecution,[4] which opened to rave reviews in London on 28 October 1953.

Unasked, Christie also wrote a role which would be suitable for Lockwood's fourteen-year-old daughter, Julia, although Margaret Barton played the part in the finished production.

Three guests currently stay with them: Sir Rowland Delahaye, Clarissa's guardian in his fifties; Hugo Birch, an irascible man in his sixties and a local justice of the peace; and Jeremy Warrender, a charismatic young secretary.

One day, while alone in the drawing room, Jeremy hastily searches an antique desk until he is interrupted by the arrival of Mildred Peake, a hearty country woman who lives in a cottage on the estate as its gardener.

The three guests then prepare to leave for the nearby golf club, as the Elgins, Clarissa's butler and cook, are taking the night off.

Clarissa tells Sir Rowland and Hugo that the house and its furnishings used to belong to Charles Sellon, a now-deceased antique dealer.

Pippa reveals a secret drawer in the antique desk containing an envelope with the autographs of Queen Victoria, John Ruskin, and Robert Browning inside.

Costello sneaks into the drawing room and searches the desk, until the door of the hidden recess opens behind him and an unseen weapon clubs him down.

There were suspicions that Sellon was involved in a drug ring, and he had left behind a note stating he had acquired an unknown item worth fourteen thousand pounds.

The Inspector decides to question every person separately, piecing together an inconsistent timeline of the three guests' whereabouts and discovering evidence that both the drawing room and Costello's body were staged.

As the Inspector is convinced Clarissa knowingly hid the body, Sir Rowland summons her to tell the police the truth.

As the Inspector starts to walk Clarissa through her self-defense story in detail, he opens the recess door to find that Costello's body has disappeared.

Pippa returns from her room and produces a wax doll; her "recipe book" was a tome on witchcraft, and she thought she had killed Costello with a legitimate magic spell.

Recalling a handful of strange interactions at the house, Clarissa realizes that Miss Peake is actually Mrs Brown, Sellon's former partner.

Miss Peake confirms her identity, explaining that the house was rented cheaply to Clarissa after Sellon died to install a different "Mrs Brown" for security.

Kenneth Tynan was a fan, writing in The Observer, "Those who grieve that our drama is a ritualistic art no longer should see Mrs. Christie's Spider’s Web and be consoled, for the detective play, in which a nameless avenger strikes down a chosen victim, is governed by conventions every bit as strict as those of Greek tragedy.

'"[8] With 744 performances Spider’s Web clearly appealed to audiences—despite mixed reviews from some critics—as it enjoyed the longest first run of any Christie play apart from The Mousetrap.

It is a twist which surprises rather than satisfies the logical mind", but they concluded, "the play as a whole is the least exciting and not the most amusing of the three Agatha Christie's now running in London."

Alvin Klein, reviewing a 1997 production for The New York Times, fell for the play's inherent comedy and the appeal of its main character, saying "What sets Spider's Web apart from most specimens of its overstuffed genre, is that its real motive is fun; all else—dropped clues, plot contrivances—is secondary.