As if answering her question, Sherlock's phone rang. He put it out of his pocket and picked it up, his eyes still fixed on the girl.

'Where?' He asked, without even letting Lestrade say anything first.

Not fifteen minutes had passed and the detective and his new assistant were in a café on Stafford Street.

'Who is she?' Asked Lestrade surprised by the view of a young girl entering the crime scene with Sherlock.

'My assistant.' Sherlock answered like it should have been obvious.

'Amber Arelun.' She presented herself to the stunt police detective with no visible intention of shaking hands with him or shining more light on the matter.

Why is she smiling like that?

'Let's focus on what's important.' Sherlock didn't want to waste any more time. He only now realized he hadn't even asked for her name before.

'We have five dead bodies.' Lestrade felt uncomfortable guessing that Sherlock was probably excited by the fact that this was not a typical crime scene. Psychopath...

He led them to a second, smaller room in the back. A couple of tables stood there, but only the largest one in the middle was occupied. Five people were sitting at it. Five men. Five dead men.

Sherlock began to walk around the table, looking at the bodies carefully. Each one of them was killed by a gunshot to the back of the head, with visible marks, the same gun every time. Killed at about the same time. Then someone tied them to chairs. Interesting.

'Names?'

'Gustav Moran.'

Tall, skinny, almost bald, despite being in his forties. Liked to brag about his wealth. Overconfident. Arrogant. Recently divorced.

'Boris Gilong.'

Red hair and mustache. Slightly corpulent. Dressed elegantly but modestly. Liked to travel. Sensitive and secretive. Had a sick mother.

'Tom Herring.'

Tall. Black hair. Red shirt, black jacket. A typical casanova. Marriage in ruins. Liked to read.

'Rupert Evans.'

Skinny. Big ears and feet. Freckled. Modest, but ambitious. With a weakness for women. Smoked.

'Moran Kamaling.'

Short. Energetic. A traditionalist. Had a strict father. His sister died when he was ten.

What do they all have in common...? Sherlock raised his eyes and saw Amber standing next to Lestrade. She was looking at the dead men, thinking. She raised her head, feeling his gaze on her.

Hypothesis?

Not really...

'When did this happen?' She turned to the inspector.

'At night. The killer broke into the coffee shop, left them like that, and disappeared.'

'They didn't leave anything behind?' asked Sherlock, leaning over and examining the table carefully, looking for any mementos.

'Not even a single hair.'

Experienced.

'This wasn't their first time.'

How did she know what was on his mind?

'They didn't leave any trace. They must have been experienced.'

'But what is the purpose of killing five famous musicians?'

He straightened up.

'Repeat that.'

'Why would they kill five favorite musicians?' Amber was a bit confused with the tone he used.

'How do you know they are musicians?' Did he miss something?

'Because I know them. Each of them either has his own orchestra or a band. Some of them are popular in the business for helping younger and talented musicians to succeed.

That's it! That's the connection. But why did they die?

'Boss, we have another dead body.' A policeman came up to Lestrade. 'Nearby.'

Sherlock clapped his hands.

'Wonderful! Let's go!'

***

This time the dead man was in the prime of his life, lying in the back of some pub. Dressed all in black, he had a gun in his bag.

'Well, we found him.' Said Sherlock calmly, leaning over the corpse.

Lestrade looked at him confused.

'Our murderer.' Amber explained to him. 'This is the paid assassin, whose task was to get rid of the five other men.'

'What do you mean?' The inspector did not understand. 'Who and why would kill an experienced murderer? And after the crime was committed?'

'He got him drunk.' Sherlock started.

'Then killed him with a gun.' Interjected Amber.

'The same one that was used to kill the others.'

'But why would he have to be killed, if he fulfilled the task he was hired to do?'

'Now, that's a good question.'

Sherlock searched the dead man's pockets and took out a small piece of paper. On it, someone had written in black ink a string of numbers.

'Interesting.' He hummed. He hid the note in his coat pocket.

'Why is it interesting? You know what it means?'

'Not yet.' The detective seemed to be in deep thought about something. But then he shook his head and left, paying no attention to flustered Lestrade. Amber followed him with a shadow of a smile on her face.

***

Back and 221B Baker Street, Sherlock leaned over the piece of paper. Think. What can it mean?

To his right was Amber, also trying to figure out the meaning behind the numbers. Her cheeks flushed with emotion and her eyes sparkling. If it weren't for the fact that others could see her too, he would have said she was just a product of his imagination. It wouldn't be the first time.

Feeling his gaze on her, Amber turned her head and met his eyes.

Something's wrong?

Nothing.

They went back to looking through the papers and notes.

'It must be some kind of cipher.' She said after a while of silence. 'After all, these digits cannot be random.'

'If it is a cipher then it's definitely a letter-for-letter type.'

'But it's not one of those criminals usually use.' She sighed. 'Maybe they used a cipher so simple that no one would have guessed it? Because why would the client write to him in cipher in the first place? As long as it was the client who wrote it.

The detectives were silent for a moment, thinking.

Suddenly, Sherlock got up and started strolling aggressively around the room. He felt that the solution was somewhere within their reach.

Amber tried to ignore him, and focused on the small piece of paper once more:

235643

What could this mean...?

Holmes's gaze rested on the note rack by the window, with an open fragment of Paganini's 21 Caprices.

Some idea appeared in his head.

'How about...'

He walked to the desk and, having quickly drawn five lines on the first sheet of paper that fell into his hand, began drawing something, muttering under his breath. Amber watched the actions of his pale fingers.

It's a stave! These numbers are the notes arranged, given their place in the scale. One number is one note, or one letter, using one of the most common scales, C-major, if you were to combine the letters then...

'One word can be written in many ways, which makes it more difficult to decipher.' He was now talking more to himself than to her.

'Degafe?' Amber read the solution.

'If you add the "e" with an accent it comes out: Degafé, a street named after a famous Frenchman on the outskirts of London.'

Amber's eyes lit up.

'So that's where we have to look for something!'

That's exactly right... his eyes answered.

She smiled broadly.

Quick cab ride to the designated place later they were looking around the small street, searching for anything. A message? A package? The only thing really on this street was the mailbox. The mailbox!

However, to their disappointment, it was empty.

'We made a mistake!'

'Or we were just late.'

Sherlock kicked angrily at the mailbox.

'Hey!'

They turned around. At the end of the street stood a police guard. He saw them and started running toward them, shouting.

Without thinking further, they threw themselves into a run. They ran as fast as they could, trying to lose the guard in the maze of narrow streets. Sherlock overtook Amber slightly and took a turn unexpectedly into some dead end, pulling the girl after him.

'What are you doing?' The only thing she could see was a brick wall in front of her. A dead end!

He pointed to a small ladder, leaning against the wall of the building.

'Quick!'

She began to climb, and Sherlock followed her.

After a while they were both standing on the roof, pulling up the ladder to prevent the guard from climbing after them. Breathing heavily, and trying to catch a breath, they started laughing.

'First day, and I've already experienced more than I have in my entire life.' Smiled Amber.

'This was just the beginning.'

He said this as if he was threatening her, but she didn't care. She was not going to give up. Not after this.