Overview
- Millie Gibson reprises her role as Ruby Sunday in the fourth episode of Season 15, marking her first major appearance since her cameo in the 2024 Christmas special.
- Ruby struggles with PTSD from her travels with the Doctor but begins to open up emotionally to her new partner, Conrad, played by Jonah Hauer-King.
- A pivotal moment in the episode sees Ruby officially join UNIT, signaling a new chapter in her life as part of Earth's defense against extraterrestrial threats.
- The episode introduces a new foe, the Shreek, adding to the series' roster of memorable adversaries.
- Ruby's wardrobe in 'Lucky Day' features a mature style, including a pinstripe outfit reminiscent of David Tennant's Doctor, subtly connecting her to the show's legacy.