The Older Brother Clause book cover by Isla Wilde

The Older Brother Clause

MF Age-Gap Forbidden Romance
by Isla Wilde

The Older Brother Clause book cover by Isla Wilde

Free with Kindle Unlimited

Pairing: MF (Age Gap 29/43)
Heat: 🌶️🌶️🌶️🌶️🌶️ Inferno
Tropes: Ex’s Older Brother, Age Gap, Forced Proximity, Praise Kink, Competence Kink, Size Difference, Secret Affair, Possessive Hero, Forbidden Romance, Slow Burn, He Fell First

She dated the charming younger brother. She should have chosen the dangerous older one.

My ex-boyfriend’s older brother warned me not to trust him.

I thought Stellan Wren was arrogant. Cold. And convinced I was not good enough for his family.

Five years later, I know he was right about his brother. I was wrong about everything else.

I need the Wrenmere Hall renovation to save my company. Stellan owns the estate, controls the budget, and watches me as if every argument costs him another piece of his restraint.

He has rules. No unauthorized changes. No entering the west wing. No involving my ex. And absolutely no acknowledging what has existed between us since the night we first met.

The final rule lasts until a storm traps us in the abandoned glasshouse and he admits he has wanted me since I was twenty-four years old.

He says giving in would be a mistake. I tell him I refuse to be one.

One night becomes a secret affair conducted between blueprints, unfinished rooms, and a family history neither of us knows how to escape. Then my ex comes home. He thinks his brother stole me. Stellan thinks loving me will destroy what remains of his family.

They are both forgetting one important thing. I am not a clause in an agreement between brothers. And I have already chosen the man I want.

You will love this book if you enjoy:

✅ Ex’s older brother with five years of hidden yearning
✅ Age-gap MF romance (29/43) where she is his equal
✅ Forced proximity in a gorgeous decaying estate
✅ Praise kink and competence kink woven into every encounter
✅ She makes the first move every time
✅ Secret affair during a twelve-week renovation
✅ Possessive hero who learns that love is not management
✅ Heroine who refuses to be called a mistake
✅ Size difference with a 6’4″ architect who works with his hands
✅ HEA guaranteed

⚠️ Content Warning: This novel contains graphic sexual content (MF), strong language, themes of family conflict, grief, parental loss, and emotional manipulation. Features a significant age gap (29/43) and power-adjacent dynamics with clear consent protections. Intended for readers 18+.


📖 Read Chapter One Free

Not sure yet? Read the full first chapter right here.


Chapter One: Tamsin

The house looked like it had been beautiful once and had spent the last thirty years being punished for it.

I leaned forward in the passenger seat as Fenella turned the rental car through a pair of wrought-iron gates that had rusted open permanently. The drive was gravel gone mossy, lined with oaks whose canopies had grown together overhead until the light came through green and broken, like stained glass in a church nobody attended anymore.

“Wrenmere Hall,” Fenella said. “Circa 1867. Thirty-seven rooms. Fourteen thousand square feet, not including outbuildings. Last significant renovation—” She paused. “1998.”

“Twenty-eight years ago.”

I exhaled. The trees opened up and the house appeared at the end of the drive like a confession someone had been holding in too long.

It was enormous. Stone and slate, three stories of Victorian ambition softened by decades of ivy and weather. The west wing was boarded shut. Plywood over windows. A section of the upper story blackened in a way that looked permanent.

Fire damage. Old fire damage.


Stellan Wren stood in the doorway holding a rolled set of structural plans, his reading glasses pushed up into hair that was darker than I remembered and dramatically more silver at the temples. He wore a charcoal henley under a canvas jacket, dark trousers, work boots that had actually seen work.

He was bigger than I remembered.

His eyes hadn’t changed. Blue-gray. Precise. The kind of eyes that catalogued a room’s structural failings in the first three seconds and spent the next thirty deciding which ones would kill you.

Right now, they were cataloguing me.

“Ms. Rooke,” he said.

“Mr. Wren.”

“I can release you from the preliminary contract without penalty. Given our personal history, I understand if the professional arrangement feels untenable.”

Stellan Wren wanted me to leave. Not because he didn’t think I could do the work. Because standing in this ruined ballroom with me was costing him something, and Stellan Wren did not enjoy costs he hadn’t budgeted for.

“Then I’m not going anywhere. You need me. And I need this project. So unless you have an actual professional reason for releasing me from this contract, I suggest we start the walkthrough.”

He extended his hand. His hand was enormous. His palm was warm, rough-callused, and broad enough that my fingers disappeared inside his grip. He shook once — firm, brief, correct — and then his hand stayed. Not gripping. Just present.

He let go. I let go. The air between us reorganized itself into something that resembled professional distance, and I followed Stellan Wren out of the ballroom and into the house he’d spent his life trying to save.


Stellan Wren looked like the kind of man who had never lost control in his life.

Naturally, I wanted to be present the first time it happened.


Want to keep reading? The full novel is available now.


🔥 Want an EXCLUSIVE Bonus Chapter?

The Drafting Table Sessions — An exclusive scene you won’t find anywhere else

Three weeks into the affair. Two in the morning. Tamsin discovers Stellan has been drawing her while she sleeps — and decides to give him something better to study. On his drafting table. On his blueprints.


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