Raffles is entertaining two friends at his home at The Albany one evening when he is visited by his old friend, Harry ""Bunny"" Manders. Bunny is goaded into a card game by Raffles' two friends, Carruthers and Tremayne, and eventually loses five hundred pounds. Having paid his debt by cheque, Bunny later confesses to Raffles that the cheque is worthless, and that his reputation will be in tatters when it becomes known.

Raffles confesses to Bunny that he is an amateur cracksman, a jewel thief who steals from the rich, but who - well, keeps the profits for himself, and invites Bunny to join him in his escapades. Bunny is surprised, but accepts Raffles' offer, and they arrange a robbery at the house of one of the men who had fleeced Bunny.

Reuben Rosenthal is a crude man from South Africa who has done well in the diamond industry. He is extremely rich and not afraid to flaunt his diamonds.

Raffles determines to have some of Rosenthal's diamonds for himself, and stakes out Rosenthal's house in St. John's Wood using a variety of ingenious disguises.

He and Bunny break and enter, but all is not smooth sailing and Bunny has a particularly rough night.

Bunny feels that he is not doing enough to justify his role in his partnership with Raffles. He suggests to Raffles that he take a more active role in their next burglary, and Raffles agrees.

Bunny arranges for their next target to be at his old home, now the residence of Lord and Lady Osborne. He arranges for Raffles to see Lady Osborne's diamonds at a party and Raffles is hooked.

But the organisational side of things is not quite as simple as Bunny had imagined it to be.

Raffles falls in love with the St. Agnes Cup, held in the British Museum Collection, and under threat of imminent purchase by a rich American. Using one of his ingenious disguises and with Bunny's help, Raffles steals the Cup from under the noses of the Security Guards at the Museum. He sends the Cup to Queen Victoria as a Jubilee present on behalf of the criminal element in Society.

Lord Thornaby, head of the famed Criminologists' Club, suspects Raffles of the crime. He invites Raffles and Bunny to a dinner given by the Club at which all members are present at Lord Thornaby's home. Raffles manages to convince them that he really is the Cleverest Cracksman of all time.

Raffles tells Bunny that he is going off to Scotland to improve his Scots dialect. During his absence his rooms at The Albany will be renovated, and it becomes imperative that certain items are not found in Raffles' flat. Therefore, Bunny is entrusted with a chest full of silver, and Raffles requests that he lodge the chest of silver with the Bank.

Bunny complies, but are things quite what they seem?

Visiting a reception at the Italian Ambassador's one evening, Raffles and Bunny conspire to steal an item of jewellery which is on display. But for the help of Faustina, a maid who works at the Embassy, they would have been caught. To repay her assistance, Raffles arranges to rescue her from the Embassy where she is being kept against her will by Count Corbucci, the evil Ambassador.

All goes well, but there is a very nasty shock in wait for Raffles, and an endless night.

Loud mouthed Barney Maguire is America's champion heavy weight boxer. At Raffles' Club one evening he brags to Raffles and Bunny that he has a trap which would trap the cleverest of Cracksmen. He also insults the noble game of cricket and ridicules his English boxing opponent.

This is enough to tempt Raffles into breaking and entering Maguire's premises, but he is unaware of the nature of the trap which awaits him. It is left to Bunny to save the day.

Somebody is setting himself up in opposition to Raffles as another gentleman thief, and Raffles doesn't like it, as he is being accused by Inspector Mackenzie of things which he did not do. Eventually Raffles pinpoints the thief as Lord Ernest Belville, and he and Bunny break into Belville's rooms in quest of some stolen loot.

Eventually there is a confrontation between Raffles and Lord Ernest Belville, and things go very wrong indeed for one of them.

Raffles has his eye on the Van Den Berg's wedding presents, but finds that he has an engagement at Lord's to play cricket on the day that they go on display, so Bunny goes in his place.

Bunny falls into the hands of Netje, the trigger-happy younger daughter of the Van Den Berg family who has taken it upon herself to guard the wedding presents from rogues and thieves.

A friend of Raffles', Teddy Garland, finds that he is in debt to the vicious moneylender, Brigstock. Raffles and Bunny pay a visit to Brigstock and manage to pay Garland's debt back.

Brigstock asks Raffles to steal a letter which is evidence in a court case pending against him. Raffles agrees, but has an agenda about which Brigstock knows nothing.

Ultimately Raffles puts Brigstock into a position where he must choose between his love for his money and life itself.

Sir Arthur Rumbold, the pompous Secretary for Home Affairs, announces that he wishes to introduce much tougher penalties for offences against property. Raffles, believing this to be a step back into the dark ages of Botany Bay and transportation for life, is furious and determines to teach Sir Arthur a lesson by burgling his own substantial London home.

Announcing to Bunny that the burglary will be an unplanned affair, Raffles goes enthusiastically to work, but it is not long before events start to go drastically wrong.

Kaiser Wilhelm of Germany is seeking to embarrass the British Government by using Herr Von Heumann, one of his agents, to hand back a priceless black pearl, which had once been a gift from Queen Victoria to her daughter, to the tribal leader from whence it originally came in the South Pacific, an area dominated by the British.

Raffles is naturally infuriated at the behaviour of the Kaiser, but he is also very interested in acquiring the pearl for his own use. He wants to be able to spend the season playing the tables at Monte Carlo with Bunny with the proceeds of the sale of it. He feels very much put on the spot when he is approached by the British Government who want him to steal the pearl for them. This conflict of interests makes Raffles play his cards very close to his chest as he endeavours to successfully acquire the pearl for himself.

Raffles and Bunny both end up joining the hunting set at a house party where Herr Von Heumann is also a guest.