Alfonso, the CEO of SoulSync Technologies, rolls out his company’s latest product: a fully autonomous AI companion who represents the ideal lover. Two junior engineers have created two such paragons: Ferrando has created the Dorabella model, and Guglielmo has invented the Fiordiligi model. Both profess their model’s perfection. Alfonso initiates a final stress test on the machines to see whether they can stay faithful under pressure (unlike, in his opinion, human women).

Fiordiligi and Dorabella awaken to their first day of autonomous consciousness. At first, they are clunky and not particularly life-like, but the two sisters show steadfast commitment to their creators / fiancés. The experiment begins with Alfonso setting up a fictional farewell: the young men have been called to the army, and their fiancées feel their first heartbreak, developing their emotional maturity.

Alfonso himself has created a Despina model – older than the two sister models by an entire week, she is worldlier and more cunning. She is forced to work as Alfonso’s maid, and she is enlisted to develop the personalities of the two new machines. Don Alfonso presents Despina with two strangers – Ferrando and Guglielmo, with subtle but effective changes to their appearance to throw off the machines’ recognition software. Don Alfonso commands Despina to encourage Fiordiligi and Dorabella to have an affair with these two foreigners. Despina, programmed to do exactly as Alfonso says, obeys – but the women are outraged at the proposition. The newcomers declare their desire for the sisters – seducing the other man’s creation (Ferrando seduces Fiordiligi, and Guglielmo seduces Dorabella). But their advances are rejected; Fiordiligi compares her fidelity to an immovable rock. The men think their inventions have passed the test, but Alfonso warns them that the experiment is not over yet.

The next test of their devotion comes in the Act I finale: the men pretend to have swallowed poison because the women spurned their propositions. The women rush to their aid, and in the process notice that the men are indeed quite attractive. They notice themselves wavering in their emotions as they are brought back to health by a mysterious doctor (Despina re-programmed) and his powerful magnets. But when the men make their most forward demand for a kiss, the women angrily refuse.