Hōrī Shitto.
This is terrifying.
Her not reaching the "non-existent" shrine is either due to the absence of Hana or due to the presence of Power Stone or both. Let's hope that the old lady arrives in time.
@Draggador the fact that the shrine doesn't even exist means that the ones helping her is not some God being that reside in a shrine. It could be the case that that thing showed Miiko an illusion that she's indeed visiting a shrine so that she wished something from it (i.e making a contract), and now it's demanding its payment. I doubt Hana nor the stone makes any difference in wether the shrine appears or not. Or maybe the stone could play a role in this, as it repels that thing's illusion shrine