It was just an ordinary rock, worn smooth and round by the eastern river, the same dull gray-brown as all the others and Mei still wasn’t sure why she had picked it up. Her brother, being a bit more adventurous, had found a bit of shell, three white rocks and a piece of driftwood burnished vaguely in the shape of a seal, if it had any shape at all. Her rock wasn’t much in comparison, so she hid it in the pocket of her overalls and shrugged empty-handed when her mother asked is she had found anything interesting.

Grownups had a very strict view of what was ‘interesting.’

It wasn’t until years later, when the twins found themselves abruptly alone following the accident, that they realized the four stones were much more interesting together than they had been alone.