Somewhere in the third unit (dark part), Yves who is now a lone star befriends ViVi. Remember when Yves kept eating apples and the red background whenever she's with ViVi? 

As you know, Yves' color is burgundy whereas ViVi's color is pastel rose. Yves, who is alone, found new comfort in her friendship with ViVi. To remain with ViVi, she has to keep eating apples given burgundy isn't her original color. By doing so, the redness of the apples helps maintaining the reddish tone in her current burgundy color; if not her color will drain back to white (Choerry already took purple in ODD EYE CIRCLE).

Meanwhile, Heejin's departure left ViViD door open :leaving the both worlds (light and dark part) exposed to one another. Haseul's slingshot aim produces another point, revealing more parts of it.  ViVi, too, noticed the crack (mirror) and caught a glimpse of LOOΠΔ 1/3 world. 

Something highlights

Surprising changes

Hyunjin came back from her Paris trip to her place in Japan. She occasionally thinks of her meeting with Heejin, even thinking of writing a letter to her. 

I close my eyes but I still think of you 

What do I do now?

It is said that Hyunjin wrote many letters to her secret crush but do note the different screenshots of her holding the letters, meaning there's another time when she wishes to deliver them to (possibly) someone else. Heejin, perhaps?

However, it is also safe to say based on these two screenshots, the first one was when she wrote to Heejin and the second one to the guy she has a crush on. Then, she went out to deliver them personally to the guy she has a crush on since he was closer.  

From Paris, Heejin further travels to Japan. Coincidentally, she met Hyunjin at a railway station who came back from seeing her crush. 

At first, Heejin failed to recognize her with a timid personality (the cat head cover).

Later, they recognize each other. Hyunjin takes Heejin on a tour of the city (I'll Be There). 

As their bond got deeper, they decided to travel together as a duo. Their next stop is Taiwan (My Sunday). 

Taiwan (also Yeojin's place) which is closer to the x-axis mirror allows Kim Lip and Jinsoul's colors (red and blue) to be refracted towards Heejin and Hyunjin's sweaters (like Haseul and Yeojin in Love Cherry Motion). Note that only red color showed varying tones through this process. Red, of all colors, has the longest wavelength in visible light thus more variation is possible.

Yeojin (in Kiss Later), like any other girls, dreams an innocent fairytale romance with Prince Charming and a 'live hapily ever after' ending. 

I see you everyday

But my heart flutters

It gets awkward for no reason

I'm still shy but I like you too

However, the dream went on not quite as Yeojin hoped thanks to the broken mirror. Assume it happened (Haseul shot a crystal piece at the mirror), as I said before, the exposure (of ViViD) was the cause. 

The after-effect somehow made Yeojin's dream and the reality fuse together in an unexpected way. 

The Frog Prince somehow came to life, with a bolder approach in romance instead. His 'tough guy' image startled young, innocent Yeojin. 

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