"They are the single most idiotic excuse for a police force I have ever seen!" Sherlock stormed into the house, flinging himself onto the couch with an angry growl.
"Their hands are tied, Sherlock. Without a warrant there's nothing else they can do." John sighed. Today had just gone from bad to worse, he was just about ready to crawl into bed. He stalked into the kitchen to make himself a cup of tea while Sherlock continued to yell.
Earlier that week a Miss Eva Blackwall had come to 221B begging for help. Apparently she was the latest victim of notorious blackmailer Charlie Milverton. She told them that he had hacked into her email address and made copies of some of her messages, messages that if read by her fiance would destroy their marriage. She said nothing more than that, clearly not wanting anyone else in on her little secret.
John expected Sherlock to pass this one up, it seemed like a normal boring "help me with my marriage isn't that what private investigators do?" type of case. Yet to his surprise Sherlock had leapt to his feet with a look close to fury.
"Milverton is quite possibly the worst man I have ever had the joy of meeting." He had told John. "I've met murderers, smugglers, drug dealers...don't give me that look John...and thieves of all kinds but he's still the worst."
So Sherlock had accepted the case, even tried to negotiate with Milverton, and when that failed he'd just insisted on using Lestrade.
"We may as well." He shrugged. "It's not an interesting case, I just want to see Charles suffer. Why not make the police useful for once?"
Then, that had failed.
"Honestly, they won't leap on any problem without a cold body." Sherlock sulked, sitting on the couch with his knees drawn up to his chest, still clothed in his coat, scarf, and shoes.
"Sounds familiar." John rolled his eyes, flopping down next to Sherlock. He slid off his shoes and grabbed the tv remote to flick through the channels until he found something mind numbing that could drown out Sherlock's ranting.
He'd only been watching for five minutes when Sherlock turned to him.
"John."
"Yes, what?"
"How would you like to be my best man?"
John choked on his tea, just managing to avoid spitting it across the room. After quite a bit of coughing John glanced up to see Sherlock looking at him with mild amusement.
"W-what did you say?" John asked, not believing his ears.
"Well? In the mood for a wedding?" Sherlock was smirking now, enjoying his little joke. Or at least John hoped it was a joke. It had to be a joke, because this was Sherlock Holmes, he would never even have a girlfriend let alone a wedding. In fact this was the one thing John held on to whenever his heart leapt at the sight of his gorgeous flatmate. If he couldn't have him at least no other would.
"A...wedding?" John asked, still in shock.
"Well you see, I've been spending some time with an Emily Georgeson lately." Sherlock smiled. "She's employed as a maid. At the house of Charlie Milverton. She's quite taken with me, so much in fact that I was able to learn quite a lot about Charlie's everyday life."
"You...?" John's mouth was still hanging open.
"I ended up having to propose to her. Unfortunately I have a hated rival due to show up and ruin the engagement any day now." Sherlock stood with a smirk and adjusted his coat like a bird might preen. "Now then, Charlie should be out tonight for his AA meeting, and because news has spread of the police being unable to obtain a warrant he will be off his guard. Fancy a break-in?"
"You...proposed to a girl...to figure out when Milverton would leave the house?" John pressed a hand to his forehead.
"Yes, we've been over that." Sherlock rolled his eyes.
"And now you want to break into his house and steal back the blackmail?" John sighed, rubbing his eyes. He was so not going to sleep tonight.
"Yes. I understand that this is illegal business and that if we're caught it will most likely hurt your reputation." Sherlock shuffled his feet as he spoke, uncharacteristically nervous. "I suppose you wouldn't want to ruin your chances of finding work by having to list being convicted of a crime...but I would be honored if you came with me."
"Well of course I'm coming with you." John sighed, pushing his shoes back on his feet. "Because otherwise you'll do something stupid. Come on then."
Sherlock never cried out "brilliant!" or "amazing!" the way John did, but his eyes did take on a look that said it for him when John agreed to coming without even thinking twice. The doctor had become a reliable partner for him ever since they'd met, and Sherlock knew that John's loyalty had saved his life on many accounts. Hopefully this time John's loyalty didn't get him arrested.

"You're sure no one else is here?" John's breath fogged the air, and he looked around nervously as he spoke. Sherlock was bent over the doorknob to the back door with a lock picking kit that John knew he had to confiscate as soon as this was over.
"Of course." Sherlock sighed. "Trust me."
The door sprang open and Sherlock beckoned the doctor inside.
"The thumbdrive we're looking for is upstairs in his safe. It holds a lot more than just Miss Blackwell's emails. You wouldn't believe how many lives he's ruining." Sherlock scowled. John studied his friend closely, wondering why this would bother him so much. He looked upon murders with glee and thefts with joy, so what made blackmail so despicable? He made a mental note to ask Mycroft later, after all whenever you found something odd with Sherlock (barring his normal oddness) you went to the elder Holmes for answers.
The two partners in crime crept through the house, Sherlock leading John into Milverton's study. The room was dark, but John could see well enough. He stood at the doorway, watching and listening for movement while Sherlock removed a rather ostentatious picture from the wall which hid a safe.
"Like we haven't seen that before." John chuckled, thinking of the time Irene thought she could keep her locked up blackmail safe from the great Sherlock Holmes.
Sherlock wasted no time dialing away the code. When John shot him a questioning glance he smirked.
"My new fiancee is a maid remember? There are few maids in the world that are not privy to their master's secrets."
John blushed and rolled his eyes, remembering how only moments before he was jealous of Sherlock's mystery woman.
Suddenly the sound of a door opening echoed through the house and the voice of a man and a woman followed. Sherlock swore, grabbing John and ducking behind the only available hiding spot: the curtain.
This is insane! We're robbing a man, hiding behind a curtain like a bunch of kids playing hide and seek! He'll see us!
The two unfortunate thieves were pressed together behind the curtain, the sounds of nighttime seeping through the window behind them. The far more threatening sound of footsteps was drawing nearer.
"...You've come to do business, yes?" The unmistakable voice of Charlie Milverton appeared in the air. John must have given some sign of his terror because suddenly Sherlock's hand was in his, giving it a reassuring squeeze. John's heart pounded, because at this sudden touch he realized just how close he was to Sherlock right now. The two of them were pressed together with Sherlock's chest on John's back, one of Sherlock's hand was on his shoulder and the other was...well he was holding it!
"I have some information on my boss, something I know she would pay greatly to have kept secret." Said the woman's voice.
"By all means don't keep me waiting." Charlie replied with some humor in his voice.
"Alright. If you don't want to wait, then I'll end the charade." The woman growled.
Sherlock parted the curtain ever so slightly, giving him and John a view of the happenings of the room. It appeared that the woman had drawn a gun from her purse and was now pressing it to Charlie's forehead.
"What are you doing?" The blackmailer squirmed, his eyes wide in fear and his voice trembling.
"You ruined my life you son of a bitch." The woman hissed through clenched teeth. "I was due for a promotion, my husband and I were going to have a family, then you ruined it all! My husband left me and I got fired! I have nothing! You stole my life from me and now I'm going to steal yours."
"Please! Don't!" Milverton screamed, but the woman just glared coldly down at him. Then there was a gunshot, and the walls were painted with Milverton's blood.
The woman placed the gun back in her purse, took one last look at her victim and then fled from the house.
John let out a breath he didn't know he was holding. "We have to get out of here." He opened the window, intending to leap from it when he noticed that Sherlock had pushed past him to get back into the room.
"What are you doing? She just killed him, we have to get out of here before we take the fall for her!" John hissed.
Sherlock ignored him and continued opening the safe. He withdrew the thumbdrive from inside it and pocketed it. By this point John could hear someone, most likely a curious neighboer, pounding on the door asking if everyone was alright.
Sherlock ran to the window and made an 'after you' gesture with a wry smile. John laughed from the thrill of it all and the two dropped into the night.
"Hey! There's someone over there!"
John swore and started running. Sherlock had already left him behind, running far ahead with an ease that didn't come to the soldier with the limp. However once Sherlock realized that John was falling behind he ran back and grabbed his hand for the second time that night, and together the two of them ran off into the night.

Modernized this one from memory so hopefully there are no errors. Go ahead and read this one: The Adventure of Charles Augustus Milverton, sometime because it's canon. Sherlock and Watson break into a house to hold hands.

Due to the popularity of Dead, Defamed, Drunken I will be creating a follow up story called "One More Miracle". Keep an eye out for it, with any luck I should publish the first chapter in the next few days.