plotdevice
nounUK /ˈplɒt dɪˌvaɪs/
US /ˈplɑːt dɪˌvaɪs/
A plot device is a trick or thing in a story that makes something happen.
The magic map was a plot device that helped the heroes find the treasure.
OTHER MEANINGS
2. An object or character used by a writer to move the story forward.
The mysterious letter was a plot device that sent the detective to the old house.
3. A convenient event or coincidence that solves a problem in a story.
The sudden storm was a plot device that forced the rivals to share a cave.
4. A clichéd element that feels forced or artificial in a narrative.
Critics called the amnesia a lazy plot device.