Overview
"Greeks Bearing Gifts" is the seventh episode of the first series of the British science fiction television series Torchwood, which was originally broadcast on the digital television channel BBC Three on 26 November 2006.
In the episode, a killer shape-changing alien called Mary (Daniela Denby-Ashe) has been stranded in Cardiff for nearly two hundred years. She seeks to retrieve a recently unearthed transporter so she can escape the planet Earth.
Plot
Torchwood is called to a building site where a centuries-old human skeleton and a rusted alien artefact have been discovered in the ground. Later, at a local bar, Toshiko meets Mary, a scavenger of alien artefacts that has been following Torchwood. Mary gives Toshiko a pendant that allows her to read minds; Toshiko promises to not tell Torchwood from whom she got it.
The next day as Toshiko examines the pendant, she reads Owen and Gwen's minds, both having dismissive and contemptuous thoughts about her. She races home, only to find Mary there; Toshiko attempts to return the pendant but Mary insists it can be used for good. Mary convinces Toshiko to read her mind again, and reveals romantic intentions for Toshiko. The two spend the night together. The next day, Toshiko asks Mary her true identity but she remains coy, answering "Philoctetes", the name of an archer from Greek mythology who was exiled on an island. Toshiko wears the pendant in a crowded street, and though overwhelmed with the thoughts of everyone, identifies one man preparing to commit murder, and she is able to follow and stop him.
From Wikipedia (CC BY-SA 4.0).