Plym Machina joins the crew of the spaceship Sophia in the series' first episode. Her background growing up alone on the streets forged strong mechanical skills, which she now applies to assist with maintenance and technical tasks aboard the spacecraft. Plym exhibits a personality marked by cheerfulness and liveliness, maintaining a generally upbeat and energetic demeanor that contributes positively to the group dynamic. Her self-reliant past and street smarts inform her practical problem-solving and readiness to assist the crew using her technical expertise. As an integral part of the central team operating the Sophia, she works alongside characters like Youth Glynnhorn, the ship's pilot, and Stella Korabelishchikov, one of the ship's doctors. Her role focuses on providing engineering support and mechanical assistance for the spacecraft and its systems.