Ep 5. The Sontaran Stratagem

The Sontaran Stratagem is the fifth episode of the first season of Doctor Who: Monsters. In this episode, the Doctor and his companion Martha find themselves in the middle of a military operation. A group calling themselves the Rattigan Academy has developed a new form of technology that promises to change the world - a series of atmospheric converters which they claim can end global warming.

But the Doctor smells a rat. He knows that no single group or person has the power to solve such a complex problem. He investigates, and soon discovers that the Rattigan Academy has been infiltrated by a group of Sontarans - a race of militaristic aliens who are determined to conquer the Earth.

The Sontarans are a well-known enemy of the Doctor, and it doesn't take him long to realize that the Rattigan Academy is just a cover for their invasion plans. The Doctor and Martha are joined by UNIT - the United Nations Intelligence Taskforce - in an attempt to prevent the Sontarans from taking over the world.

This episode is filled with action and excitement as the Doctor and his team battle the Sontarans. The Sontarans are a formidable enemy, with their advanced technology and warrior culture. The Doctor has to use all of his wits and ingenuity to stop their invasion plans.

There are plenty of tense moments in this episode as the Doctor and Martha race against time to stop the Sontarans. There are also some great moments of humor as the Doctor clashes with the arrogant leader of the Rattigan Academy, a teenage prodigy named Luke Rattigan.

Overall, The Sontaran Stratagem is a thrilling episode of Doctor Who: Monsters. It's a great showcase for one of the Doctor's most iconic enemies, and fans of the show will love seeing the Doctor face off against the Sontarans once again.