Two sets of mixed fraternal twins, Cane and Awan as well as Eva and Seth, are on an unnamed planet on which people are connected in "hive' minds via devices implanted in the backs of their necks, and on which the culture is highly logical and utilitarian.
Because they have a high degree of telepathic rapport, they are chosen for a colonization mission to Earth, after a space probe transmits Beethoven's Fifth—which they recognize as evidence of intelligent life but whose purpose they don't clearly understand, as there apparently is no music for artistic purposes on their planet.
As the ship approaches Earth, Eva receives instructions from Mission Control, via Seth, to land in a body of water near a city, and to release a live virus to render the human race extinct to prepare for colonization by the home world.
Cane uses a shard of broken glass to cut the telepathic receiver out of his neck, enters a room with what appear to be fetuses in artificial wombs but may be their "virus", and attempts to shut down the virus program before Eva knocks him out and places him in a stasis chamber.
She asks Cane for help, and when he returns with a glass shard, she cuts the telepathic receiver out of her neck.
[3] In The Times Ed Potton calls it a “script full of promise, with provocative things to say about empathy, obedience, and individualism”.