When Sherlock was ten or so, they emigrated from _________. The rest of family adapted to human culture much better than little Sherlock, who stubornly refuses to learn the customs of his new home planet beyond the bare necessities.

He's doing fine until ... John.

Now he reluctantly conceeds that he may need to assimilate a bit better and asks big brother for lessons on being just normal enough to win over the only human to capture his attention.

(Feel free to make this a fusion or crossover with anything at all, or original.)

RTYI's welcome!