The Doctor is back in the lives of Grant, Lucy, and their daughter Jennifer. He's on a mission to find the other three alien gemstones, siblings of the one that gave Grant his superheroic powers – and only Grant can lead the way! Following the gems' trail through time, the four ended up in a future New York City ruled by the fearsome entity known as The Smoke – and reclaimed one gem. They set off in the TARDIS and arrived at their next destination... a world where the Harmony Shoal has taken over! But Grant's powers have ceased working – just as he and the Doctor are in the direst of straits.

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