First words. First steps. Tiny things like first smile, first laugh, the first time he reaches out and grabs Sally's finger (and his hands are so small). Sherlock misses everything. The real reason Sally Donovan hates Sherlock so much? They have a child he never sees.
This one is a gut punch. It's a riveting experience - not pleasant but meaningful - and an entirely unusual take on Sherlock Holmes in a kidfic.
Spot On - Characterization good enough that when it shows you a side of a character you don't want to believe, you believe it anyway.