Zhan Tiri pays a visit to the Demanitus Chamber and reveals her plan to her old enemy that when the solar eclipse comes, she'll draw the power of the Sun Drop and Moonstone to herself. Also, to make sure that Rapunzel and Cassandra never rekindled their bond, she has a plan in motion.
Later, Rapunzel hears from a little boy that Gothel's ghost was haunting Cass' childhood home and goes to investigate it. To her surprise and confusion, the ghost turned out to be a fake. But as she wonders why someone wanted people to think Gothel's ghost is there, Cassandra arrives and starts a fight with her. But during the fight, a black rock tilts the house over and opens a secret passageway, which Rapunzel and Cassandra fell into. They soon find themselves trapped in an underground mine.
Cassandra attempts to break out with black rocks, but it only released poisonous gas from underground. Rapunzel suggests that they should work together to escape. Cassandra refuses at first, but after seeing how bad the situation is, she gave in.
While looking for a way back to the surface, the girls find a room full of mirrors and papers similar to the Demanitus scroll. When they touch the mirrors, it projects Gothel talking to herself about her day and her beauty. When one of the mirrors shows Gothel telling little Cassandra to sweep quieter in a mean way, Cass begins to question if her own mother really loved her. However, one of the mirrors was missing and, unbeknownst to them, Zhan Tiri slips it into Rapunzel's handbag.
When Rapunzel tries to reach out to Cassandra again, a spilt chemical catches fire and traps them again. Rapunzel soon gets an idea to follow the bats to the exit and using a mine cart to speed past a giant mole. But just when the girls start to bond again, Cassandra finds a hand mirror in Rapunzel's bag and it shows Mother Gothel giving little Cassandra a music box so that she "can think of her dear, sweet mother and the love [she] has for [her]." Thinking that Rapunzel knew about it and was trying to hide it from her, Cassandra gets angry and leaves her to die in a cave filling with poisonous gas.
Fortunately, Pascal gets a giant mole to break though a wall to get Rapunzel the fresh air she needs to live. When Rapunzel revives, she makes a promise to never give up on Cass. Meanwhile, Cassandra returns to her tower and tells Zhan Tiri that she was right about Rapunzel. Zhan Tiri fakes her sympathy for Cassandra and secretly throws away a piece of the hand mirror, which reveals that the true reason Gothel brought a music box was to keep Cassandra, whom she views as a pest, out of her hair.
- Mandy Moore as Rapunzel
- Eden Espinosa as Cassandra
- Hudson D'Andrea as Little Cassandra
- Donna Murphy as Mother Gothel
- Jennifer Veal as Zhan Tiri
- Parker Bates as Seth
- Ramone Hamilton as Kid
- Dee Bradley Baker as Baby Mole
- This title is a pun on the Charles Dickens novel A Tale of Two Cities.
- The episode shares its title with the Once Upon a Time episode "A Tale of Two Sisters".
- Rapunzel makes a reference to her past encounters with Ruthless Ruth and the Dark Kings in "The Wrath of Ruthless Ruth" and "Destinies Collide".
- This is the third episode where Eugene does not make an appearance, following "The Wrath of Ruthless Ruth" and "Day of the Animals".
- However Eugene is mentioned as "my boyfriend", by Rapunzel.
- One of Gothel's notes on the Sun Drop, its Healing Incantation, and the Moonstone appears to be a self made copy of the Demanitus Scroll.
- Cassandra's cape looks very similar to Gothel's signature cloak.
- The way Cassandra briefly regrets abandoning Rapunzel and leaving her to suffocate to death in a cave, is similar to the way Gothel momentarily hesitates to abandon young Cassandra in the "Rapunzel's Return" flashback, only to shrug it off.