My Brother's Best Friend, My Secret F1 Lover

Sienna's POV

By ten o'clock, the whole wedding had moved out to the garden for fireworks.

Everyone was crowded on the lawn with sparklers and champagne, Olivia's grandmother shrieking every time a rocket went up. Noah had his arms wrapped around his new wife, both of them staring at the sky like teenagers.

Nobody was watching the house.

I slipped off my heels, hooked them on two fingers, and headed for the back staircase. Ten more steps and I'd be in my room, out of this dress, and done pretending I hadn't just signed a contract to follow my one-night stand around the world for an entire season.

I made it to the third step.

"You're missing the show."

Kai was leaning against the banister at the bottom of the stairs, half in shadow. The clear garment bag hung from one finger, my red dress glowing through the plastic like a warning sign. The torn seam gaped right down the middle.

"I brought your dress back," he said.

"Great. Now bring back my dignity."

"That one's going to take longer." He held up the bag. "I brought it over from the hotel this afternoon. Plain box, my name on the label. Nobody opened it. Nobody saw it."

"You're sure?"

"I carried it up here myself. Your brother thinks it's a spare suit."

I came back down the steps and reached for the hanger. He didn't pull it away this time. But his sleeve had ridden up, and in the porch light that pale scar ran clear up his forearm, smooth and shiny against the tan.

My hand stopped.

I suddenly remembered a phone call years ago, Noah sounding exhausted in a way I'd never heard before. *My friend crashed. He's a driver. They don't know if he'll race again.* I'd said I was sorry and asked if he was eating enough, and then I'd forgotten about it.

I'd never asked for a name.

"What?" Kai said.

"Nothing." I took my hand back. "We need to talk. Not out here."

---

The library on the second floor was empty, lit only by one brass lamp on the desk. Somewhere between the fireworks and the stairs, it had started to rain. Water streaked down the tall windows and blurred the garden lights into gold smears.

I spread the filming schedule across the desk. Jules had already sent the full calendar, and I'd printed it in the bridal suite like a psychopath.

"Bahrain. Jeddah. Melbourne." I tapped each one. "Paddock access, garage access, the team hotel. I'm with Mara Ortiz almost every day."

Kai dropped onto the leather sofa and rubbed his jaw. "I'm back at the factory Tuesday. Simulator work, then media day."

"Which I'll be filming."

"Which you'll be filming." He looked at me. "So we keep it clean. Work is work."

"Obviously."

"And whatever happened in Monaco stays in Monaco."

"Obviously," I said again, and hated how fast it came out.

He watched me for a second too long. The rain ticked against the glass.

"You don't sound sure."

I folded my arms. "Look. We're adults. It was one night, and it was good. I'm not going to pretend I don't want to climb you right now, because we both know I'd be lying." His eyebrows went up. I kept going before I lost my nerve. "But I'm also not going to turn this into some big complicated thing. So if it's still there, we deal with it like grown-ups. We make terms."

"Terms," Kai repeated.

"No dates. No feelings. No one finds out."

He leaned forward, elbows on his knees. "Friends with benefits?"

"Strictly benefits."

That got a laugh out of him, short and surprised. "Wow. You're cold."

"I'm efficient."

There was a pad of wedding stationery on the desk, cream paper with *Noah & Olivia* printed in gold across the top. A few white rose petals had fallen onto it from the centerpiece. I brushed them aside, grabbed the black pen next to the lamp, and started writing.

"One," I said. "Noah never knows."

"Agreed."

"Two. We don't mess with each other's work. You don't ask me to cut footage. I don't ask you for inside gossip."

"Fine."

"Three. Nothing in public. No dinners, no walking into the hotel together."

"Four?"

I paused with the pen over the paper. "If anyone gets serious, it's over."

He was quiet. Then he got up, came around the desk, and held out his hand for the pen.

I gave it to him. He bent over the paper, close enough that his shoulder brushed mine, and wrote in neat block letters.

*5. If either of us is uncomfortable, it stops. Anytime. No explanation needed.*

He added *K.M.* beneath the list.

I read it twice. It was the same thing he'd asked me last night, with his hand on my cheek. *Tell me to stop, and I stop.*

"That's a good rule," I said, quieter than I meant to.

"It's the only one I actually care about."

I cleared my throat and took the pen back. "Do you treat every woman like a race? Rules, regulations, penalties?"

Kai tilted his head toward the paper, then toward the pen in my hand.

"Sweetheart," he said, "who picked up the pen first?"

I opened my mouth. Nothing good came out.

I tore the sheet off, folded it into a tight square, and shoved it into my clutch.

"One more thing," I said. "Not a rule. A fact. You are not coming to my room tonight."

"Okay."

"I mean it. Noah's room is next door to mine, and he checks on me when he's drunk."

"Okay," he said again, perfectly easy, already stepping back.

I waited for the argument. The grin. The *you sure about that?*

It didn't come. He just picked up a rose petal from the desk, turned it over in his fingers, and nodded at the door like I was free to go.

It was exactly what I'd asked for. It annoyed me anyway.

"Good night, Kai."

"Good night, Sienna."

I walked out with my heels in one hand and my clutch in the other. I was halfway down the hall before I realized the garment bag was still draped over the arm of that leather sofa.

I didn't go back.

---

My room was dark. The fireworks had stopped, and the rain had gotten louder. I sat on the edge of the bed, still in the sage-green dress, and stared at the folded square of paper sticking out of my clutch.

Ten minutes. That was all it took.

My phone lit up on the comforter, the screen bright enough to make me squint.

*Your dress is still in my room.*

No emoji. No question mark. Nothing I could hold against him.

I typed *Keep it* and deleted it. I typed *Leave it outside my door* and deleted that too, because Noah would trip over it at three a.m. and ask questions I didn't have answers to.

Then I stood up.

The guest wing was at the far end of the villa, down a long hallway lit by a few weak sconces. The tile was cold under my bare feet. Laughter drifted up from the terrace below, and every time a door creaked somewhere, my heart jumped into my throat.

*It's just a dress,* I told myself. *Get it and leave.*

The brass plate on the last door read *Suite 7*. Of course it did.

I didn't knock. The handle turned.

Kai was standing by the window with his back against the frame, rain running down the glass behind him. His jacket was gone, his sleeves rolled to the elbow, the scar pale in the lamplight. The garment bag hung from the closet door, red silk glowing through the plastic.

He didn't look surprised to see me at all.

I stepped inside and shut the door behind me. The lock clicked under my hand.

"This changes nothing, Kai."

He pushed off the window, slow and unhurried, and didn't come any closer. He just looked at me, waiting, the same way he had last night.

"Then come here," he said softly, "and prove it."