At the museum they meet up with one of Soo Lin's co-workers, Andy. He tells them Soo Lin had indeed left three days earlier but didn't believe she would just up and leave. She had been working on restoring ancient Chinese tea pots and doing traditional tea ceremonies.
Andy shows down to the basement where the work would be put away at the end of the day. Instead they find a statue with the warning message sprayed on it.
Upon leaving the museum Raz finds them and leads them to a hidden skate area in the undercroft, the underworld of London, where graffiti covers a majority of the walls, the symbols peek out from the other splashes of color.
The two leave Raz behind as they split up to look for more evidence of the painted symbols.
John finds himself wandering down some railroad tracks alone, in the dark with only his flashlight to see by. His progress is slow but he can't even remember the last time he slept or even the last thing he ate. John isn't as focused as he should be but so far he had come up with nothing and knowing Sherlock they were going to be out there out all night until they found something or passed out.
John is on the verge of calling it quits and just calling himself a cab but he knew he couldn't leave without Sherlock. Sighing he pulls his jacket tighter and walks on. Passing a lone brick John flashes his light at it and stops to look at the multitude of symbols decorating the surface.
His entire being is flooded with relief and he stares at it as he phones Sherlock who doesn't answer, nor does he answer the other times he tries. Frustrated John snaps a photo and proceeds to look for the annoying berk.
"Answer your phone," John yells when he finally finds Sherlock, "I've been calling. I found it."
Sherlock straights from his crouched position to follow after John.
Back at the wall John finds it strangely blank. He blinks several times just to be sure but it is indeed void of all symbols and yellow paint. In fact the wall looks as if it had never had anything on it at all.
"I don't understand...it was here, ten minutes ago I saw it! A whole lot of graffiti." John protests glancing at Sherlock.
Sherlock studies the wall a moment. "Somebody doesn't want me to see it." Suddenly he turns to John and grabs his face between his hands.
"Sherlock!" John protests.
"Shhh John," Sherlock tells him, "I need you to concentrate, close your eyes."
"What, why?" The doctor asks.
Sherlock lowers his hand to John's shoulders.
John glances at them. "What are you doing?"
Sherlock ignores him and begins to spin them slowly, keeping eye contact with John the entire time. "I need to maximize your visual memory, can you picture what you saw?"
Thinking back to the picture he had taken John nods, "Yeah."
Sherlock looks skeptical, "can you remember it?" He asks.
"Yes, definitely." John replies trying to free his arms but Sherlock tightens his grip.
"How much can you remember?" Sherlock questions.
John frowns at him. "Well, don't worry…" He tries but gets interrupted.
"Because the average human memory on visual matters is only sixty-two percent accurate." Sherlock tells him.
"I remember all of it." He assures.
Sherlock gives him a disbelieving look, "Really?"
John pulls himself away from Sherlock, "At least I would if I could get to my pocket, and I took a picture." He says getting his phone out. Quickly he pulls up the pictures of the wall and shows them to Sherlock.
Sherlock really enjoys touching John and getting close to John.