[3 days before the departure of Jeongyeon, Tzuyu, Yeji and Ryujin from the Moon]

There is an invincible orbit that surrounds the Sun, wherein there is a city in it. The red-orange flame part of the orbit, somewhat closest to the Sun, is the main capital of Apollo. The Royal families and Energizer families normally live there for the families to meet up easily.

The blue part of the orbit ring is occupied by the government in control, where all Apollo lives there for their working or study life.

The other part of the orbit is actually the residential area where some other Apollo doesn't like to stay in the busy city, since the commuting is easy for them, so they stay further from the capital or the city, and still could get there easily.

Like the Moon, there are invincible space aircrafts taking of from the orbit and reaching to the other side of it, and yet the Earthlings never knew this because the Sun is too hot for them to approach.

"Shin Yuna! Where are you?!" 

Shin Yuna, a girl with long crimson-red hair was riding on her flamy pheonix, on her way to the main capital of Apollo.

"On my pheonix!" Yuna shouted happily towards her hand band communication device.

"On your—you mean, on your way?" The other girl on the other side of the line asked.

Yuna laughed merrily, "No Lia unnie! I’m riding on a pheonix! My pheonix."

"How come you get a pheonix on your own?" Lia, on the other side of the line asked again. "Nevermind it! Tell me later! Are you near the capital yet?"

Yuna glanced downwards from her phoenix and answered, "Almost there! You'll see me in three, two—"

With a swoosh, Yuna urged her pheonix to glide downwards to a flame-red mansion, and as both approached the ground, Yuna tapped her pheonix symbol on her wrist and the pheonix was "kept" into her body through the sign, with her stumbling a little to stand on the solid ground.

Upon seeing Lia's mouth was hung agape (which is hard to see, because Lia normally maintained her image well), Yuna grinned, "One! I'm here!"

Lia was dazed when she saw Yuna was really riding a pheonix towards the mansion and she was stunned right now. Yuna hummed at Lia's condition and turned to the steel gate of the mansion.

"It's time we go in, eh? Lia unnie?" Yuna asked the dazed elder girl.

Snapping out of her daze, Lia closed and led Yuna into the automatically opening gate. "So how did you get a pheonix? I mean, yeah, you're under the trainings of the Minatozaki's, and you had a symbol of them, but how?"

"Sana unnie taught me this morning, so I went for a ride before coming here," Yuna said with a wide grin. The thought of having her own pheonix was much too exciting for her. 

"Sana unnie? My god, Nayeon unnie haven't even taught me how to summon my own Kirin," Lia sighed. "Anyways, this is the first time we've been here to meet Queen Apollo, so mind your words, okay? I know you can sometimes get too excited and say too many things, resulting in TMI..."

"TMI?" Yuna asked nonchalantly, looking at the flowers planted along the garden path to the main mansion. 

"...Too much information," Lia answered. "Don't you know that? I thought you surf the Earth's internet a lot."

"No, I only watch kdramas and watch music shows."

Lia facepalmed, "I thought you're Sana unnie's student not Nayeon unnie's?"

"Well yeah, but they're besties, they watch kdramas and cry together."

As expected from the two childish mentors.

"So, have you seen Queen Apollo before?" Yuna asked, her mind bringing up the image of Queen Apollo.

Like the Artemis, Apollo's have their King or Queen named after Apollo, hiding their identities. They would also wear a flame-red mask, and only the ones closest to them will know about their identity. However, the King or Queen is directly descended from the Royal families, which means the big three families - Park, Minatozaki and Im families. For the Minatozaki and Im, they are also the two famous Energizer families among the others; while for the Park's, they are descended purely from the first royal family.

Although the Artemis will have their King or Queen chosen from any class of family, the current King or Queen Apollo will have to choose their next heir from the only three Royal families. To prevent chaotic competition of choosing the King or Queen, once the heir is chosen, he or she will live a double life as the trainee of the current King or Queen and the family member of his or hers. Only when they succeeded, they can choose to tell their family, or friends, or keep the secret by themselves.

"No, my first meeting here is with the previous King when I came here with my dad. The era has changed and I haven't met Queen Apollo yet," Lia shook her head, nonetheless her eyes sparkled with anticipation. "I'm looking forward to meet the current Queen. She'd made changes to the Apollo's that there will not be any divison of classes, which means even we who are not directly descended from the Royal families or Energizer families will be able to join as a trainee in the Royal families!"

"I heard that Queen Artemis from the Moon also made this change, following our Queen's step," Yuna nodded, "I wish I could see what's on the Moon if I get the chance."

They stopped walking as they reached the front door of the mansion. 

"We're here," Lia announced.

Yuna gulped nervously. She's bubbly and cheerful, yes, but she's still haven't met the Queen before, and when she realized she's nervous she's already standing in front of the door, carved with a symbol of Sun. "Lia unnie..."

Lia hummed in confusion, later realizing Yuna was tugging on her shirt lightly. She gave a knowing smile and held Yuna's hand.

Yuna's still young. She's only turning sixteen years old this December, and yet here she was, being the strongest Energizer trainee among the Minatozaki's family, waiting to accept her mission to be able to qualify as the Second Energizer of the current Minatozaki family. And obviously Lia was going to accept her mission to qualify herself as the Second Energizer of the Im family.

Well, the First Energizer of the Minatozaki and Im's are Sana and Nayeon respectively, who are the mentors of Yuna and Lia.

As they held hands, Lia pushed the door open and led Yuna in. A man in a maroon suit nodded towards them, "Queen Apollo is in the second room on the right side of the hallway, second floor."

"Thank you," both girls gave a light bow to the man, continuing to walk to the second floor.

Beside the staircase was a wall with the paintings of the previous Kings and Queens, and there's also some Energizers who brought energy to the people on Earth, and also the solar system.

The job of an Energizer is simple: to bring joy, energy and hope to people, regardless of the Apollo themselves, Artemis, or the Earthlings. Energizers can also control fire, in contrast to the Artemis, who controls water.

Being the cheerful and refreshing Yuna, she had been one of the strongest Energizer in the history of the Minatozaki's family. As for Lia, although Yuna may be more powerful than her, Nayeon sees potential