So the possum which wasn't sick? Is now missing.
Which wouldn't be a problem except that her baby is not missing: he spent yesterday tucked up tight in their makeshift nest, curled up and pretending to be nothing more than a knot of leaves on the balcony, hoping against hope that the big frightening people wouldn't notice him until his mother returns. Except she was away all day yesterday, and maybe even all day the day before because no one checked on her.
So I spent last night trapping the little fella and taking him to the nearest wildlife shelter. Possums are extremely territorial, and by law must be released within 50m of where they're captured, so when he's old enough I guess he'll be released back near us again anyway. And if mother possum turns up a quick phonecall to the shelter will see baby brought back. But I'm not hopeful on that last score: still no sign of her this morning.