After the death of their mother, Elizabeth and Paul, orphaned brother and sister left to their own devices and bound by an exclusive affection, live together in their large Parisian apartment.
They have built themselves a chimeric universe governed by sibylline symbols. Their room is a real sanctuary where a "treasure" is enthroned with a meaning that is also known only to them. "Elizabeth" met Michael and married him, but the next day he died in an accident without their marriage having been consummated.
She inherited Michael's fortune, including a large private mansion where Paul came to join her with their famous treasure. Gérard, a comrade of Paul and his friend Agathe, who strangely resembles Dargelos (a schoolboy that Paul idolized), soon come to live with them. But when Elizabeth understands that love is born between her brother and Agatha, like a Greek divinity, a kind of Parque, she weaves a Machiavellian web so that her brother cannot escape it. As in all ancient tragedies, the outcome can only be fatal.
Fascinating by the morbid desire carried by the Paul/Elisabeth relationship, this seemingly banal story hides a tragedy: the inevitable end of adolescence, its myths, its grace, its illusions. Elizabeth and Paul die for breaking this law by wanting to eternalize a moment of passage. Indeed, as soon as Dargelos' snowball reaches Paul in the chest, time stops, "the room" begins to live. It became their deserted island, the little piece of land isolated from the rest of the world where they built cabins with their pillows and led a Robinson's existence at night. Their bodies grow, Paul's legs protrude under his sheets, they play at having the desires of grown-ups; but in fact, nothing moves. If they move, it's to rebuild the room immediately. Behind their incessant quarrels, their constant agitation, there is a morbid desire for immobility...
It was Dargelos, the hidden god of this tragedy, who precipitated its outcome by sending a poisoned black ball to Paul, who completed the work of the first snowball. Elizabeth, priestess of the chamber, is only the instrument of fate. By killing herself and her brother, she brings their adolescence into eternity.