Summary: Harry bets John that he can't ask Sherlock to do something.

Author's note: This came to me all of a sudden whilst I was out Christmas shopping. The object mentioned in this fic actually exists. I saw it in a shop and couldn't believe it.

I hope you enjoy it, I don't think it is the best thing I've written though.

The Bet

The turn in Harry and John's relationship had come when she had stopped drinking. It hadn't been easy for her. She had hoped to get back together with Clara. Full of hope Harry had told Clara she had given up the drink. But Clara had said that she'd 'moved on'. Harry had been devastated, but to her credit she had tried to keep off the alcohol. She'd called John in desperation one evening, begging for his help. He had stayed with her for two weeks and managed to help her get over the worst without her resorting to alcohol. After that Harry had gone from strength to strength. She lived and worked in London as well, so John and Harry tentatively agreed to meet for lunch occasionally. Seeing her in small doses meant they the both seemed to get along a lot better than they had done in years. She wasn't a different person without the drink, but her personality shone through more without it. She was still irritating, brash and downright selfish at times, but she was also funny and smart.

It was approaching Christmas which was rapidly becoming John's least favourite time of the year. Everything cost money. Everything was more expensive. He has headaches when he thought about his credit card bill in January. Usually when he met Harry for lunch he would argue with her as to who would pay. This time however John simply couldn't afford to offer. As their plates were cleared away by the waiter, Harry leaned forward placing her elbows on the table.

"I have a challenge for you. Call it a bet." She said grinning wickedly. This was becoming a feature of their relationship. Harry would come up with an idea, and bet John that he wouldn't do something. John would accept and win the money from her. They both knew that this was Harry's method of getting John to accept financial aid from her, but in an unspoken agreement they didn't mention it. John sighed thinking of his credit card bill.

"What is it?" Harry's eyes shone. She brought out a small packet wrapped in Christmas paper from her bag and placed it gingerly on the table. John frowned.

"What is it?" He repeated. She told him. His eyes widened in horror. He squeezed the packet and a faint rendition of 'Rudolf the red nose reindeer' could be heard coming from it.

"No! If you think I'm..."

"I wasn't thinking of you. I was thinking of Sherlock." Harry said still grinning.

John just stared at her.

"No." He said flatly.

"Not even for five hundred pounds?" She said with a low whisper.

"I can't afford that!" John gasped.

"Ah but I haven't told you the best bit." She leaned back in her chair. "Conditions are: One, if you accept the bet and don't succeed I get exquisite gloating rights. Two, you can use any method to persuade him. You can even tell him that it is a bet to win five hundred pounds. Three you don't even have to prove it. Just tell me you did it, and I'll believe you. I know you are appalling honest." John paused then shook his head.

"Still no."

"Hmm, I thought my money was perfectly safe. The real challenge would be you asking him!" Harry laughed. John suddenly narrowed his eyes.

"Any method?" John said. Harry's eyes lit up.

"Yes."

"Five hundred pounds?" John asked.

"Oh yes. Ask him, persuade him and the five hundred is yours little bro. But you'll never do it."

John did take the small packet back to Baker street. He hid it in his pocket. Harry had said he could pull out of the bet any time he wished. She would just gloat and sing the occasional 'I told you so' song. He mounted the stairs still thinking. Five hundred pounds would certainly make his life easier. It would pay a few outstanding bills that were lying in a pile in his room glaring at him. Harry was right. The real challenge would be actually brooking the subject with Sherlock in the first place. As he entered the living room he saw Sherlock lying on the couch staring fixedly at the ceiling. Around the flat were the unmistakable signs of boredom. Sherlock, when bored, was as easily distracted as a kitten. He would start things then abandoned them half-way through when he got bored. John's gun was in pieces (since he couldn't blow holes in the wall as John had hidden the bullets), the computer was on and a web page was on the screen which had clearly been discarded and there was an unpleasant smell coming from the kitchen which John decided not to investigate. Sherlock looked at him intently.

"Harry gave you a gift." Sherlock said.

"No!" The reply came back too quickly and suddenly and John saw to his despair that he had accidentally peeked Sherlock's interest. He tried to laugh it off.

"Well that is...a bet we have." He said.

"What bet?" Sherlock asked curiously, but John had left and was heading quickly up to his room. Harry had chosen her moment very well, but not on purpose. Had Sherlock been in the midst of a case for example, he would not have been remotely interested. Sherlock narrowed his eyes in the direction of John's room thinking. Harry had bet John to do something. From John's reaction it is something he finds embarrassing. There must be a lot of money involved or John would not have accepted the bet. John purposefully headed out of the way when he had asked about the nature of the bet. If it was something embarrassing that John had to do he would not have wanted to admit to it but he would not have run away, therefore it was something to do with him. Sherlock smiled, got up from the couch and walked towards John's room.

John had placed the packet in the middle of his bed. He looked at it for a long time before finally shaking his head. No, Harry was right, he couldn't do it. He had brought out his phone to call her when the door to his room opened.

"Sherlock!" John exclaimed. "Look please don't just..."

"What's the bet John?" Sherlock asked. "Harry asked you to ask me to do something didn't she?"

"Er yes how did you..? Never mind." John shook his head. "It's stupid and I'm not going to do it."

"And lose the bet?" Sherlock asked.

"It's not that serious. Harry just gets to gloat."

"Oh."

"She is a champion gloater. She'd give Moriarty a run for his money." John said.

"And if you won?" Sherlock asked. John hesitated before replying.

"Five hundred pounds." Sherlock raised both eyebrows.

"But I'm not going to...Sherlock!" John exclaimed as Sherlock darted forward and snatched the packet up from the bed. As his hand closed around it, the faint tune began to play. He saw John turn red.

"It plays a tune...well I say tune..." Sherlock said dissapproving at the badly played noise coming from the packet. John stared at it.

"I was supposed to ask you to wear them."

"Them?" Sherlock asked curiously. "Are these musical socks? I've seen those in the shops." John said nothing. Sherlock opened the packet and lifted out the contents. He frowned and put the offending item on the bed.

"I see."

"It was her idea." John said protectively suddenly feeling like a schoolboy in front of his headmaster. A long pause followed.

"Fine. Where and when do we met your sister?"

"W...What?" John felt as though the whole situation was slipping away from him.

"Presumably she requires some sort of proof." Sherlock said in that I'm being patient and you're being an idiot voice.

"You're going to do it?" John said disbelievingly.

"I should have thought that was obvious. Really John I didn't think you'd want to turn down five hundred pounds so readily."

John was too stunned to think straight.

"She said I didn't have to prove..."

"Oh I think it would be better if you did. Don't you think?" Sherlock said. Certainly seeing Harry's stunned expression might be worth it.

"I'll call her. Are you sure?" John asked.

"Yes." Sherlock said and putting the item in his pocket he left the room. John wasn't sure what he found more embarrassing. The fact that Harry had bought the item in the first place with Sherlock in mind, this conversation with Sherlock in his bedroom, of the fact Sherlock had agreed to wear a musical red thong with cartoon picture of Rudolf on the front.

Merry Christmas!