Despite not being translated it still manages to both cute and heartwarming.

So... They were all going to check out a haunted house, Ren drew the short straw and had to go in first... Heard a piano, somehow knew it was Miku, decided to come by later... found her, took her outside, she freaked out, not knowing she could go outside... then... um...

I confused myself.

xctman said:
...found her, took her outside, she freaked out, not knowing she could go outside... then... um...

By keeping his promise and returning for Miku, he freed her spirit from wandering... probably.

Tetrominon said:
By keeping his promise and returning for Miku, he freed her spirit from wandering... probably.

That sounds about right
Most Ghost stories goes, That Ones you rest a soul in peace, it moves on

Doing that means over coming its restrains
Anger, Sorrow, What ever the reason ghost wanders