While he is convalescing the pair sing duets and exchange vows of undying affection.

But the military Briton, who has invaded the country at large, must needs now invade also this cosey abode of love.

Frederick, a brother officer, discovers Gerald and informs him that duty calls (Britain always expects every man to do his duty, no matter what the consequences to him) and he must march with his regiment.

Frederick has happened in just as Lakme is gone for some sacred water in which she and Gerald were to pledge eternal love for each other, to each other.
But, spurred on by Frederick and the memory that "England expects, etc.," Gerald finds the call of the fife and drum more potent than the voice of love.

Lakme, psychologist as well as botanist, understands the struggle which now takes place in Gerald's soul, and relieves him, of his dilemma by crushing a poisonous flower (to be exact, the Datura stramonium) between her teeth, dying, it would seem, to the pious delight of her father, who "ecstatically" beholds her dwelling with Brahma.
The story, borrowed by Gondinet and Gille from the little romance "Le Mariage de Loti," is worthless except to furnish motives for tropical scenery, Hindu dresses, and Oriental music.