A bust of the Roman emperor Nero has been found. It has some odd properties: it has an inner heat source, it leaks condensation from a crack in its base, it causes dizziness and fatigue to anyone who touches it briefly, and it burns anyone who holds it for any length of time.
The bust has been taken from the museum and brought to the University of Rome to be studied. Liz Shaw is assigned by UNIT to study it. For several hours a day, however, the bust is displayed to the public, as the curator of the university's gallery hopes to bring in money from the exhibit.
One day as Liz enters her lab, she notices a stranger examining the bust. He introduces himself as Dr Jonas Smythe, sent by Colonel Chaudhry to act as her assistant. She gives him all the information she has, and he suggests they use an electroencephalograph to examine the interior of the bust. Liz thinks she can get one and they leave the lab.
The caretaker, Claudio Terrizzi, comes to get the bust for its daily display in the gallery. He is fond of the bust and takes good care of it. At the gallery, Smythe and Liz, after retrieving the EEG, head for the gallery to observe the crowd.
A man carrying a sweater makes his way through the crowd to the bust and suddenly grabs it, wrapping it in the sweater. He runs off, pushing aside a security guard and Smythe. Another guard, Liz and Smythe give chase. As the thief runs outside, his way is blocked by Claudio's cart, and he and Smythe crash into it. The thief loses the bust and it hits the ground, breaking off Nero's nose. Before the thief loses consciousness, he claims the bust was talking to him.
Back at the lab, Liz and Smythe use the EEG on the bust. They determine that it responds to and can manipulate heat, especially body heat. Smythe theorises that there is a creature inside the marble that has been buried for millions of years. They decide to neutralise it so Smythe can take it to UNIT, and leave in search of a container of liquid nitrogen.
Claudio enters the lab and is disgusted at the wires hooked up to Nero. The bust implores him to take it away. He tries to do so, but soon loses consciousness. The bust draws the heat from Claudio, and soon the lab is on fire. The fire is quickly contained by firefighters, but Claudio has been incinerated.
Liz and Smythe return in time to see the wreckage of her lab. The fire chief allows them to search the record for their "dangerous experiment". They retrieve the bust and drop it in the liquid nitrogen. Something squirms around inside, then Smythe covers the container. They evade the fire chief's questions by referring him to UNIT.
Smythe says goodbye. As Liz is driven home, she finds a note in her pocket requesting her to tell the Brigadier that the Doctor says hi. She wonders what the Doctor's involvement in this incident was.
- The Doctor uses the alias Dr Jonas Smythe.
- Smythe reminds Liz of a man she used to work with at UNIT.
- The Doctor tells Liz that Colonel Chaudhry sent him to work as her assistant.
- This story was reprinted in Short Trips: Re:Collections.
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