Saiga likes inviting people with deformed eyes to his parties.

Sui shows up at Hikari's place, handing her a sealed envelope and saying that Kei has a job for her. Maybe not. Kei shows up to take the letter back, but in her usual spastic way, Hikari insists on accepting the 'challenge'. The 'job' turns out to be going to a party with Kei as his partner. (So uh, Hikari is working as Kei's escort?)

Sui is a trap.

In preparation, Hikari makes a dress, but of course it's terrible, so Kei has to make preparations to have one custom-made. Hikari is a bit too much to handle for the seamstress, since her sides are ticklish and she flips out whenever her waist is measured. One of the tailors comes up, who appears to be familiar with both Kei and Hikari; and he proceeds to creep the heck out of her.

C~reep

It all ends well though, as Kei is initially mesmerized by Hikari's appearance. At the party, Kei gives Hikari instructions not to talk to anyone, and he goes off to greet people. Bored, Hikari finds her way to the balcony, where she's approached by the tailor from earlier. Turns out he's actually Saiga Yahiro, the very person for whom this birthday party was thrown for. Saiga enlightens Hikari about Kei's unrequited love for her, saying that if he puts the moves on her right now, Kei will definitely interfere. He's about to force a kiss on Hikari when sure enough, Kei knocks him aside. Hikari is surprised, and when Kei asks her what Saiga told her, she becomes embarrassed and runs off.

Why did this scene last for 6 whole seconds? ?_?

Reunited later at the party, Saiga makes an announcement of a game of 'inverse tag' where the person who is 'it' must run from the rest. Winner who reaches the roof gets a prize, etc. Hikari is chosen, and she's soon faced with some of the partygoers, who she promptly beats up. Finding the dress hard to move in, she rips it down to size. However, she's suddenly pulled into a room by Kei, who asks her to escape in the car he's prepared. She refuses, saying that she must meet Saiga's challenge. Hikari slips through Kei's hand, which is apparently a big deal because they made a watercolor scene of it.

Kei settles for stalling the others so that Hikari can win, and she does. She's greeted by Saiga on the rooftop, who asks her if she wants jewels, cars or a villa. Hikari responds that she wants Saiga to recognize her as Kei's rival. He refuses. Just kidding. Why in the world would anyone refuse a request like that? Just before Hikari and Kei go, Saiga asks about Akira. It turns out that Kei, Saiga, and Akira were childhood friends.
On the way back, Kei continues to ask Hikari what Saiga told her. Of course, she's definitely not telling.

Thoughts:
Well, this episode didn't really get anywhere, but now Hikari knows that Kei likes her. (Well, maybe not knows. Well, at least the idea NOW EXISTS in her head.) All thanks to our creepy what-are-your-intentions Saiga. Prediction for next episode: Hikari goes completely emo over wondering if Kei really likes her and overthinks it way too much. Believe it.
Akira may be getting more screentime? Saiga seems to care for her, after all. Not that we like Saiga, or anything. Don't know what his motives are but seems like he's a chauvinist.