Ep 6. The Poison Sky

In Doctor Who, Monsters: The Sontarans season 1 episode 6, titled "The Poison Sky," the Doctor and his companion, Martha Jones, find themselves in the midst of an alien invasion led by the warmongering Sontarans. The Sontarans, a race of militaristic clone warriors, have come to Earth with a plan to turn its atmosphere into a poisonous gas that will render the planet uninhabitable for humans, allowing them to claim it as their own.

The Doctor and Martha team up with UNIT, the United Nations Intelligence Taskforce, to try and stop the Sontaran's plan. However, things quickly go awry when the Sontarans infiltrate UNIT's base and take control, forcing the Doctor and Martha to go on the run. With time running out, they must find a way to stop the Sontarans before it's too late.

As the Doctor and Martha race against the clock, they encounter a number of Sontaran soldiers and their commander, General Staal. Staal is a ruthless warrior who is determined to carry out the Sontaran's mission at any cost. He sees the Doctor as a worthy opponent and engages in a battle of wits with him throughout the episode.

Meanwhile, Martha is forced to confront her own fears as she helps UNIT's commander, Colonel Mace, coordinate a counterattack against the Sontarans. She also gets to showcase her own intelligence and ingenuity as she comes up with a plan to hack into the Sontaran's communication network and gain valuable information.

As the episode reaches its climax, the Doctor and Martha confront Staal and the Sontarans in a final showdown. With the fate of the planet hanging in the balance, the Doctor must use all his wit and intelligence to outsmart the Sontarans and save the day.

Overall, "The Poison Sky" is a thrilling and action-packed episode that showcases the Sontarans as one of Doctor Who's most formidable monsters. The episode features plenty of intense battles and heart-stopping moments that will keep viewers on the edge of their seats until the very end.