- San Toy - Daughter of Yen How
- Captain Bobbie Preston - Son of Sir George Bingo
- Yen How - A Mandarin
- Sir Bingo Preston - British Consul at Pynka Pong
- Sing Hi - President of the Board of Ceremonies
- Lieut. Harvey Tucker
- Fo Hop - A Chinese Student
- Fang - A Boatman
- Hu Pi & Wai Ho - Jewellers of Pynka
- Li Hi & Li Lo - Tartar Guards
- Old Mandarin - At Court of Peking
- Poppy - Daughter of Sir Bingo
- Dudley - Her Maid
- Chu - A Widow
- Wun Lung - Perpetual Corporal of the Emperor's Own
- Ko Fan - Of the Emperor's Own
- Yeng Shi, Me Koui, Siou, Shuey Pin Sing, Li Kiang
& Hu Yu - Wives of Yen How
- Mrs Hartley Streeter
- Hon Mrs Hay Stackporle
- Miss Mary Lambkin
- Lady Pickleton
It is the Feast of the Full Moon in the town of Pynka Pong (No. 1 - 'We'll keep the feast in Pynka Pong') where Sir Bing Preston is the British Consul. Two jade merchants (Hu Pi and Wai Ho) try to bribe Li, the private secretary of the mandarin Yen How (No. 2 - 'The Mandarin'). Li takes the bribes and flirts with Dudley, 'The Lady's Maid' at the British Consulate (No. 3). Li is actually in love with Ko Fan, who is in Peking where she has been conscripted as one of the Mandarin's female guards, the Emperor's Own - the fate of all noble daughters. The consul's daughter, Poppy Preston, sings over some flowers sent to her from England (No. 4 - 'A posy from over the sea').
The mandarin Yen How, who has 'Six little wives' (No. 5), has got around the conscription law for his favourite daughter, San Toy, by having her brought up as a boy. Unfortunately, the student Fo Hop discovered the secret and his price for silence is San Toy's hand in marriage. Yen How allows this on the condition that no one must ever know that San Toy is a girl - and thus preventing the marriage ever from happening.
San Toy is herself in love with the Consul's son Bobbie (No. 6 - 'The petals of the plum tree'). While her father was away, she was teaching Bobbie his 'ABC' (No. 7). Unfortunately, a marriage between them would never be countenanced by either of their fathers.
The ceremony of the Festival of the Full Moon takes place (No. 8 - 'The Moon') and a quartet expounds the delights of 'Pynka Pong' (No. 9). Bobbie must leave San Toy to go to Peking on his father's business and departs sadly (No. 10 - 'Love has come from Lotus Land'). Their love seen is seen by Fo Hop, who tells San Toy how he will turn her into the model Chinese wife (No. 11 - 'When you are wed to me'). Li and Dudley, meanwhile, agree that love and marriage is the 'Samee gamee' all over the world (No. 12).
A new edict from the Emperor is announced, ordering that now all sons, as well as daughters, of Mandarins must join a new regiment in Peking, so San Toy must depart for Peking, where she resolves to be a girl at last, joining Bobbie's boat. Yen How declares that he will also go to Peking and petition the Emperor to return his daughter (No. 13 - Finale Act I).
Act 2 is set in the Emperor's Palace at Peking, opening with a chorus of Mandarins (No. 14 - 'We're the cream of courtly creatures'). The Emperor enters and San Toy is introduced to him - and he is charmed by her, telling her that she will be treated with great favour.
Li now arrives, followed by Dudley, who entertains the Emperor with the hit song 'Rhoda and her Pagoda' (No. 15). There is an entrance chorus for 'The Emperor's Own' (No. 16), followed by the Preston family and consulate staff (No. 17 - 'By our majestic Monarch's command'). Poppy explains Western marriage customs (No. 18 - 'The whole story'). A pas seul is danced (No. 19). San Toy assures Bobbie that she is still his 'Little China Maid' (No. 20). Yen How and his wives now enter (No. 21 - 'We have come to see').
Li, hiding inside a china figure to avoid some pursuing guards, sings a duet with Dudley (No. 22 - 'Pletty little Chinee'). The English party sing of how they long to get 'Back to London' (No. 23). Yen How, seeing in what favour San Toy is held by the Emperor, plans for the day when he is made Viceroy and introduces the benefits of British life into his country (No. 24 - 'I mean to introduce it into China').
Bobbie sings to San Toy (No. 25 - 'The One in the World') and San Toy sings an allegorical song about 'The Butterfly' (No. 26). Li sings another irrelevant song about the soldiers of different nations (No. 27 - 'Chinee soje-man') before it is declared that the Emperor is astrologically ill-suited to San Toy but very well-suited to one of the Emperor's Own, leaving San Toy free to marry Bobbie, Li to his old love Ko Fan and Yen How to be promoted to Viceroy (No. 28 - 'Finale Act 2')
A re-working of the score for the lower vocal range of Ada Reeve, who took over the role of San Toy from Marie Tempest, produced the songs 'It's nice to be a boy sometimes' (No. 29) and 'A little bit of fun' (No. 31). 'Somebody' (No. 32) was an extra song for San Toy, while 'Me gettee out very quick' (No. 30) was, at one time, sung by Li in Act 2.