"Itsuka, Taiyou no Moto De (Someday, Under the Sun)" is an audio-only play that was included with the Transformers: KissPlay toy Convoy X Melissa (Convoy Meets Marissa). It stars Lyrian as Marissa, and Tessho Genda (the voice of the original Convoy in Japan) as Convoy.
The following is a synopsis and partial transcript of the 10 minute play.

We hear the sounds of ocean waves.

Marissa whimpers and asks why the nights in Japan are so cold.

Convoy apologizes for the fact that he can only let her surf at such a late hour.

She quickly reassures him that he does not need to worry; surfing while gazing at the moon feels good, too.

Convoy says that some day, he would like for both of them to go surfing under the sunlight.

Marissa agrees.

Suddenly...

"Oh, Convoy! Your shift lever is dirty," Marissa exclaims. "It must be from when I spilled soft serve ice cream on you before. I will wipe it clean for you now."

She giggles as Convoy gasps and moans. "It t-t-tickles!" he says.

"Is this the right spot?" Marissa playfully asks as he begs her to stop.

Convoy changes the subject and announces that they have reached the usual place. The truck rolls to a stop.

"We have nice waves tonight," Marissa says contentedly. "I can't see them very well, but I can tell from the sound."
She gets out of Convoy. "Well then, I'm going!"

She runs off through the sand, calling out, "Convoy, please take care of things here!"
Then she turns around and runs back with a giggle.
"I forgot my surfboard."

Convoy chuckles affectionately. "You're as scatterbrained as usual." Then he becomes serious. "Take good care of that surfboard, for that surfboard is--"

"Bye, Convoy!" she chirps as she runs off again.

"Marissa..." Convoy murmurs. "Some day, beneath the sun..."

Out in the water, Marissa sighs. "It's a little cold, but it feels good. Convoy looks so small already."
She makes a small sound of surprise. There is something slimy touching her leg!

Back on the beach, Convoy muses to himself.
"Marissa's gotten a little fat lately," he says. "She's eating too much soft serve ice cream. Hm, today even her swimming looks a little funny. She clearly needs to go on a diet."

"Convoy!" Marissa cries out. "Convoy!"

"Marissa! What on earth has happened!?"

"He'p! He'p!" she replies in (bad) English.

"Tch! Is the E.D.C. around?" Convoy asks. When he is certain that it is safe, he shouts:
"TRANSFORM!"
*G1 transformation sound*

"I'm coming! Marissa!" Convoy calls out, splashing loudly through the water. Panting, he nears the girl. "Are you all right, Marissa?"

"Convoy...something creepy is tangled around my leg!" she squeals.

"Hm? Is that all..."

"Oh...it's starting to come up further...oh no, not there!" she protests.

"Just hold on. I've almost got it," he reassures her.

"What is it? What is it??"

There are wet slippery noises. "It's...a squid!" Convoy declares.

"It's slimy...it's gross..." Marissa whimpers.

Convoy sighs. "I was very worried about you. Hold on, I'll remove it."

Marissa sighs in relief. "Thank you, Convoy. I can always count on you."

"Honestly," he says in exasperation. "I'm going back. We never know when the E.D.C. might show up."

As he splashes away, Marissa screams again. "Convoy! He'p! He'p! Ohmigaw!"

"What is it this time?" Convoy asks. Spotting Marissa's latest molestor, he declares: "...It's an octopus!"

"It's an octopus!" she helpfully tells him.

"Oh, for... What am I going to do with you?" he sighs.

Convoy swims back toward Marissa. As he nears her, he exclaims in surprise. "What? What's this...!"

"It's an octopus...it's big!" cries Marissa.

"What is this enormous octopus!?" wonders Convoy.

Exciting music blares! Monster noises are heard!

"Convoy! Heee'p!" Marissa wails.

"So it's a Legion unit!" Convoy says. "Then the corruption has spread to the molluscs as well. It's completed a ParasiTech fusion with a shipwreck!"

"Convoy, it's getting hard to breathe..."

"You bastard! Get your feet, I mean your hands...oh, I don't care which it is. Get your hands and feet off of her!"

The monster roars.
"DOOOAAAAAAAH!" Convoy shouts as the battle is joined. He has difficulty fighting because of the creature's soft body. "I can't grab it!"

There is a splash. Convoy has evidently been knocked into the water.

"Oh, now I'm mad," Marissa declares. "I'm going to take this knife and..."
The Legion beast screams in pain.
Marissa cries out as the creature tosses her away. "Please let me go more gently!"

"Marissa! Where are you?" Convoy shouts.

"Here I am," Marissa replies. "I seem to be okay. What about you, Convoy?"

"I'm fine," Convoy says. Then he groans and moans.

"Convoy! Something is spilling out of you!"

We hear a trickle and electric sparking. "It's just a minor injury," Convoy assures her.

"Stay still," Marissa gently instructs as her voice becomes echoey. "I will now use my power...this kiss... Convoy and I will become one."

There is a loud smooch and triumphant music. "Convoy, let's go!" Marissa cries.

"I've got a good idea!" Convoy says. "I'm going to borrow your surfboard."
We hear a transformation sound.

"Oh! The Surfblade!" says Marissa.

"As long as your kind exists," he tells the Legion monster, "we will--" His voice trails off.

"Take this!" both cry out in unison.

After the battle...

"Oh, thank you, Convoy," says Marissa. "I was saved by you again."

"The same goes for you, Marissa," Convoy replies. "If I had not been saved by you, then who knows what would have happened?"

Marissa nods. "Let's go home, Convoy. The sun is coming up. It's morning already."

Convoy agrees. Suddenly, a siren pierces the beach's still morning air.

"Convoy, it's an Autrooper! We've got to run away!"

"Dammit!"

The siren stops.

"The girl with glasses who's driving...she's gotten out of the car. She doesn't look like she's feeling well. Uh...do Japanese drivers get carsick? Oh...the Autrooper is rubbing her back," observes Marissa.

"That doesn't matter. Climb aboard me, Marissa! TRANSFORM! Quickly, get on!" Convoy instructs.

"Some day, we can go to the sea under the sun, can't we, Convoy?" she hurriedly asks.

"Yes, of course. But now isn't the time. Now hurry!"

"It's a promise!" Marissa insists.

The truck drives away.

"Marissa..." whispers Convoy. "Someday...I promise."

Layout elements from CSSplay.co.uk and Mari's IROEMPITSU