Because It's Sentimental SAGA is the sixth episode of Zombieland saga.
While looking up details about the Saga Rock Festival, Ai discovers that her old group, Iron Frill, will be part of the line-up.
Later, as Franchouchou hold a photo op session with a small group of fans, Ai and Junko clash with each other over their different opinions on how idols should interact with their fans.
Sakura hears from Junko about how hard she tried to become an idol in life, only to die in a plane crash before her first tour; feeling her outdated mindset on idols is hindering the other girls, Junko contemplates leaving Franchouchou.
Meanwhile, Saki learns from Ai about how her death from a lightning strike during an outdoor concert left her with a fear of lightning and a determination not to just be a part of history. The next day, Kotaro announces that Franchouchou will be a part of Saga Rock, causing both Ai and Junko to feel uneasy.