In addition to Samantha Morton reprising the role of Alpha in this episode, Scarlett Blum also reprised the role of Lydia. She also played young Lydia in season 9 episode 10, "Omega", of "The Walking Dead".
References in song sung by Lydia about Lydia:
- Battle of Waterloo - took place in Belgium on June 18, 1815, marked the final defeat of Napoléon Bonaparte, by the Englishman Arthur Wellesley (Duke of Wellington), who conquered much of Europe in the early 19th century.
- Wreck of the Hesperus - a poem by Henry Wadsworth Longfellow, about father and his small daughter who die when their ship hits rocks during a storm. The phrase like the "wreck of the Hesperus" may be used to mean 'very untidy' or 'in a ruined state'. Hesperus itself, is the Greek equivalent for Roman Goddess Venus, the Goddess of Love.