Hmmm.

...And this is that?

Yes.

There are several, but this is one.

You don't grip this key with your hand,

but with your heart.

Both undoing and inverting...

It all depends on your heart.

So don't open and close locks indiscriminately, alright?

If I can't just try it on every lock, how am I supposed to look for the right one?

That won't be an issue.

You can simply walk around as you see fit.

The lock and the key will call out to each other.

So long as you wish for the incident's resolution,

that call will continue to echo.

So long as your heart, to the very end...

...continues to wish for it...