Work Text:
Harvey and Donna never really had boundary issues. She used to listen into all the conversations going on behind her. He used to find out about the speed dating and played with the guys that tried bedding her.
So when Mike and Harvey were out on a work lunch with a new client, she went and picked the drawer that held the papers that he got from a genetic company a few weeks ago. Looking over, she saw that Harvey had gotten his DNA checked against someone. It didn't even take three guesses and she was laughing. Things were going to be fun.
She started saying things like 'Dad needs you' when Harvey wanted him. Her list of comparisons became bigger as she watched them working together and apart. Half the time she wondered if Mike was just picking it up by being around for long periods of times, but there were things that people don't copy. Like coffee orders, or putting hot sauce on pepper jack cheeseburgers.
Donna was surprised, but delighted when Mike started playing along, calling him 'Dad' also. He couldn't decide whether she was a sister, aunt or something else. Definitely not Mom or Step-mom as he tried once and was extremely terrified worried about her reaction to the words. He settled on step-sister, because there was no way the red hair could be directly related to him. Harvey hadn't realized what quite was happening. Rachel overheard them once and started laughing along with Donna when Mike complained. She was careful. Lewis never heard the remarks, neither did Jessica. And she did all she could to keep Harvey from hearing it.
“Sure, I'll get these to 'Dad',” Donna joked, grabbing the files out of Mike's hand and setting them on her desk. Harvey was supposed to be 'reviewing a case' when he was really taking a nap. Some meeting that had run over, she wasn't sure. She didn't bother turning off her intercom because of that and didn't notice Harvey until he grabbed the files off her desk and motioned her into his office.
“Turn it off first, I don't anyone listening in,” he ordered. Donna switched off the intercom and closed the door. “When?”
“A few weeks ago,” she shrugged.
“The file?”
“Top left drawer,” she confirmed.
“Who else knows?”
“Only me,” she assured. He raised an eyebrow at that. “He hasn't even guessed it. Rachel overheard and just laughed at it. They don't actually suspect you're his biological father.”
He nodded at the answer, satisfied that no one actually knew. “Also, how and when exactly did I marry your mother?” he questioned.
“I think we decided three years ago when Mike was going through fake-college. It was a very lovely ceremony. Jessica bought your vacation,” she told him.
“Huh,” he paused, “And here I thought you were going to make Jessica my wife.” She smirked and walked out. That's going in the story.