Hi! A lovely anon at tumblr sent the following prompt that inspired this one-shot:

"Someone (not Diggle) wondering why Oliver has a key to an apartment that isn't his (its Felicity's). Super mega bonus points if they find out whose apartment it's to and how/why Oliver got the key."

So here it goes :)

Doesn't contain spoilers

Enjoy!

THE KEY

"Ollie, what's this key for?"

"What?" He turned around and faced Thea, who stood with a hand on her hip, an accusatory eyebrow raised and his keys in her hand. His eyes widened in surprise when he noticed the key she had singled out: Felicity's.

"It… is for the storage at the bar." He lied warily. "The one where I keep the good stuff for special occasions."

"Special occasions?" She knit her eyebrows at him, unconvinced by his feeble excuse.

"Uh, meetings, with important clients" he struggled. For someone who had a secret identity he was awful at lying, at least to his loved ones.

"Right…" she conceded, being well aware there was more to it that he let on.

Oliver walked to her, snatched the keys from her hands and told her with a smile "Still chasing after me, Speedy. It's good to see that some things never change". He dropped a kiss on top of her head and headed out, scolding himself for being terrible at making lies on the go.

It didn't escape to her how flustered his brother was. Thea Queen wasn't easily fooled and now was determined to figure this little mystery out. She looked down and opened her palm, revealing the unknown key. Fortunately she had quick hands. She smiled haughtily: now her quest begun.

Her first stop was Roy's. Much to her dislike, he had knowledge about breaking and entering, and surely could tell her more about the key. And he did.

Roy assured her it wasn't for the club. While unloading the stock he had familiarized himself with every storage place there was. He even knew about the secret underground level, where he would run off for a quick training with Diggle or Oliver whenever he could. But he didn't tell her that much.

"It's from a lock, an apartment door most likely" he said, examining the key. "That's as much I can tell from it alone".

"I knew you'd be useful for something, Harper" she teased him. She pressed her mouth to his and before he could respond she waltzed away.

Next she turned to Diggle, Oliver's trusty bodyguard. Although he never talked about it Thea knew they were friends, a stronger bond having formed over time. After all it had been almost three years since he had started shadowing her brother.

"Diggle… can I call you John?" she asked, innocently. He nodded, a small smile on his face. "I was wondering, since you drive Ollie around most of the times… Is he seeing somebody?"

A chuckle escaped his lips before he could stop it, and then cleared his throat to mask his reaction. "I don't think it's my place to answer that."

She smiled cheerfully, now having her answer. "So could you point me to the right direction?"

Though he had a straight face now, he said with a playful voice "His assistant. There might be something in his schedule to help you out". She thanked him with a silent nod and walked into Queen Consolidated.

Oliver climbed off his bike and headed into the building, greeting the doorman on his way.

Today was their first anniversary, and he was making her a surprise dinner. It marked 365 days since he had made the best decision of his life. He had fought against his feeling for Felicity for a long time, until they were both nearly broken; but ever since he had let her in everything had changed. She made him smile, even through the wreckage that was his life.

Still they had decided to keep their relationship between themselves, to avoid unnecessary problems. Half their lives were already lived in the shadows, so they'd managed to make their romance survive that way. Of course Diggle had found out, just by noticing the small changes in their exchanges, but had respected their wish for privacy.

A smile spread on his face, remembering how Diggle had walked in on them making out in the foundry once. He climbed the familiar steps until he was in front of her door, and reached for the keys in his pocket. There was a handful there, but not the one he needed the most. Confused he studied the ones in his keychain until realization hit him: Thea.

His meddling, curious little sister. First he smiled at her antics until his brain caught up with him. He knew exactly what Thea would do: dig up. And also who she would turn to eventually. He stormed down the stairs, climbed on his bike and rushed through the streets towards his office.

The ding of the elevator startled Felicity. She had been singing along to a playful tune while researching some arrow business when Thea Queen walked up to her desk. It was unusual for the young Queen to be at their offices, Felicity had mostly run into her at the club or at company events. Yet there she was, curious eyes darting to her brother's office.

"Oliver isn't here" Felicity quipped. "He's out doing some… business" she raked her brain trying to remember where Oliver was but came up short. When he left a few hours ago he had vaguely stated that he some business to attend to.

Thea look at her, a mischievous look on her face. "It's ok; I was actually looking for you."

"Me?"

"Yes" she said and pulled a key from her purse. Felicity's brow furrowed recognizing said key.

"How did you get my key?" she voiced, words leaving her lips before she could contain them.

Thea's eyes widened as she put the pieces of the puzzle together. Her brother's 'special occasions' had a name, one she had known for quite a while. She had suspected Felicity was more than just Ollie's assistant, his brother's eyes lingering on the blonde girl longer than socially acceptable; but now she had proof.

"Oh everything makes so much sense now" she said as her mouth rose in a smile. "Ollie sure has been holding onto you!"

"What?" At Thea's raised eyebrow Felicity blushed. She knew. But had Oliver told her? She didn't think he would without her permission. Panic rose in her and all she could think was deny. "No, Oliv… Mr. Queen doesn't have a hold on me. I'm not on hold at all. Not that I'm not serious about my job, I am, I'm not going anywhere." She rumbled on, words tripping from her mouth on their own volition. Thea looked amused, her smile growing as Felicity's speech got more out of hand.

"So this isn't Ollie's key to your place?" she asked, already knowing the answer. Felicity was even a worse liar than her brother was.

"No. I mean yes, it is, but not like that. It's for emergencies, like watering plants and caring for my cat. Though I don't own a cat, yet, but if I did…" Thankfully the elevator doors opened, the distraction stopping her train of thought.

Oliver darted into the room, the worried look on his face deepening at the sight of Thea standing before his girlfriend's desk. Felicity met his eyes and smiled coyly at him.

"I'm sorry" she mouthed, as Thea turned around and smiled knowingly at him.

"So how late am I to congratulate you two?" she said teasingly.

He swallowed and walked to her side. "Thea, this is my girlfriend, Felicity" he declared, proudly. Then turned to Felicity and raised his eyebrows at her.

"I saw this going differently in my mind" she said, a faint blush creeping over her cheeks.

Thank you for reading! Please like/comment. As always, encouragement or constructive criticism is always welcomed :)