"John, I feel… tired. I'm going to bed, we can work on the case tomorrow."
"Are you sure you're alright? You don't normally get tired Sherlock, especially if you have a case on."
"I'll be fine"
However the next morning it became very evident that Sherlock was sick. John was woken by a feeble poke in his side just before his alarm went off. When the alarm went off a few seconds later Sherlock responded by covering his ears with his hands and murmuring 'make it stop' weakly.
"Sherlock, you are staying in bed today. No case for you."
"But, I'll get bored."
"Then I'll have to make sure you don't. Hot Ribena or Lemsip?"
"What?"
"To drink idiot. I'm looking after you!"
"I don't need looking after, I'm not that sick."
"Liar. You just want to play around with the case."
"Lemsip." Sherlock had apparently given in to John. However when John returned a few minutes later Sherlock was attempting to get up.
"Back in bed. Now."
"My head hurts."
"You got up too quickly drink this." Sherlock took the cup from John and allowed him to help prop him up. He was a little confused when John began to leave.
"Wait! You're meant to be keeping me entertained!"
"Well I was going to wheel the T.V in so we could watch the security tapes but if you want me to stay…" John said with a grin on his face.
"Tapes, please!" John laughed at his insane flatmate and went to get the television.
A few hours of boring tape later the boys finally found what they were looking for. It was Half five, one of the busiest points of the day. Louisa (or 'Lou') was sat on one of the seats in the carriage. When the tube stopped at a platform the carriage emptied until there were four people left. Louisa, two men and one woman. The train then pulled forward and Louisa stood up (probably to get off at the next stop) suddenly the woman makes a quick jerky movement and Louisa collapses. The other people in the carriage rush to her side.
A nice little cliff-hanger for you all, the deductions are coming soon