Tween Sherlock is delighted that Mycroft is home for a few days from university. However, he's not happy at all when Mycroft, who was supposed to spend time with him, suddenly changes plans and leaves him with a babysitter - the government wants to consult him about something important.
Sherlock rages and insists that he's too old for a babysitter - in fact, Mycroft used to babysit him when he was his age - but Mycroft isn't impressed by the tantrum and tells him to behave with the (carefully selected) babysitter.
Mycroft returns home late in the evening, and finds the babysitter in tears. Sherlock is missing. She explains that everything was going well during the first hour - she's a chemistry major, and she and Sherlock were getting along as they did experiments together (and as Sherlock bragged about the government wanting to consult his brother for something very important and very secret, but she doesn't mention that part) - but then the boy suddenly became stroppy when she tried to convince him to eat dinner, and fled the house.
Mycroft looks around and quickly deduces that Sherlock went to a hidden little spot in the neighbours' garden. He assures the babysitter that everything is fine, apologises for his little brother's behaviour (she replies that it's okay, that Sherlock is a great kid who was probably just upset that he couldn't spend time with his idol), and tells her to go home.
Sherlock, who regrets having run away by now (and feels guilty, because he actually liked the babysitter), is even more unhappy when he hears his big brother's approaching footsteps (that he perfectly recognises) - he knows he's in for it.
Mycroft is indeed clearly displeased as he tells him to get him, and leads him back to the house.
However, the first thing Mycroft does when they get home is to heat a big pot of soup (prepared by their housekeeper). He noticed that Sherlock's skin was very cold and that he was shivering as they made their way home, and he hasn't had any dinner, so making sure that he eats hot soup is his top priority. (The next priority will be a hot bath.)
