This is Chapter One of the manga Fushigiboshi no Futagohime: Lovely Kingdom.
The chapter begins with Princess Grace's history. The Blessing of the Sun weakened one years ago. Princess Grace of the Sunny Kingdom used Prominence and sacrificed her own life to save the Wonder Planet and restore the Blessing.
Then it shows Princess Fine urging her sister Princess Rein to hurry as a party at their castle is going to begin. Fine has the idea of picking flowers to use them for a greeting they have planned for those who will come to attend. As the two rush to the gardens they muse on how much they're looking forward to the party, for different reasons.
Rein is excited to see Prince Bright in person, who she has only seen in portraits up until then. Meanwhile Fine is most excited about all the delicious food that will be present.
Arriving at the garden the two notice that the flowers in the garden look quite wilted and wonder why, but they don't dwell on it for long as they see the other kingdom's airships beginning to arrive. The twins grab a ladder and hurry off despite the maids around questioning what they're doing. The twins climb to the roof and throw the flowers up in the air, welcoming the royals from the other kingdoms.
There are three specific people who notice the princesses' welcome: Prince Bright of the Jewelry Kingdom, Princess Mirlo of the Waterdrop Kingdom, and Eclipse, who is simply referred to as a "mysterious youth". Bright believes them to be high spirited while Mirlo thinks they're acting like savages.
As the twins celebrate their successful welcome they slip and fall from the roof. Rein pleas for someone to help them and Princess Grace answers the call while informing them of the danger the Wonder Planet is in. Grace tells them that the Blessing is weakening once again, the wilting flowers are proof of it. Grace bestows them with Prominence and asks them to protect the Blessing. Shortly after the two muse about this a chest falls onto Fine's head. When the girls open it they meet Poomo. When Poomo confirms the twins' desire to fulfill Grace's request he begins to explain how to use their newfound power.
Fine and Rein, however, quickly grow bored of Poomo's long-winded explanation. Fine uses Prominence to freeze Poomo in place to stop his talking. As the twins celebrate their newfound magic actually working they feel like they're forgetting something. Finally it dawns on them that they forgot about the party! The two scramble to the castle and once they arrive they find the ballroom to be completely frozen!
Mirlo admits that she is responsible for it thanks to her Drop Wand. She calls the frozen ballroom a "masterpiece" claiming how the ballroom was before was dreary and hardly fit for herself, the "most beautiful princess of the Wonder Planet". When the twins get mad and tell her to change the ballroom back to normal she attempts to use the Drop Wand on them! Luckily, they are rescued by Prince Bright. When the princesses fall to the ground he also offers to help them up. Rein graciously accepts, but Fine refuses as she gets up herself which seems to catch Bright's interest.
Mirlo is upset that Bright can't recognize the beauty of her creations and says he's "not as great as [she] thought". Then she says she refuses to undo her spell. Rein suggests to Fine that they use Prominence to get rid of the ice themselves! Once they transform Poomo appears and tell them that Grace once wore the dress herself. The twins recite the spell and all the ice in the ballroom is turned into delicious shaved ice that everyone can enjoy!
Everyone starts to eat the shaved ice except for Rein who notices that Eclipse is staring intently at herself and Fine. She calls him "scary looking" and tells Fine about him. However, Fine seemed to have a different opinion as she began to blush upon seeing him. Rein snaps her out of it and soon Mirlo comes trudging over, upset that they ruined her decorations, saying that the "most beautiful princess" no longer has any decorations worthy of her. The twins counter by saying that Mirlo could never be truly beautiful if she continues to cause trouble for others. Mirlo takes this as a challenge and comes up with the Princess Parties.
Fine is eager to participate, but Rein hesitates until Bright says he believes she and Fine have a good chance at winning. Mirlo announces that the theme is a beauty contest where everyone will have to dress their best. Bright wishes Rein and Fine luck, but Fine is too busy wondering where Eclipse ran off to. She is interrupted form her thoughts by Rein who tells her sister that they must win at all costs.
As the twins converse Mirlo orders one of her beaver servants to shoot an arrow with a message towards the twins. They read the message that tells them if they use dragons scales form the Sky Dragon to make a dress it will be the cutest dress on the entire planet. Poomo feels that it's suspicious and says it my be a trap, but the twins ignore him and decide to go find the dragon anyways. Mirlo smirks and calls the girls stupid for believing the message so easily before saying that the two will surely give up upon seeing how terrible the Sky Dragon is.
The chapter ends with Rein musing that she and Fine are unsure if they can protect the Wonder Planet, but they'll do their best and become marvelous princesses!