The exploration goes without issue; now, to find the ghost Tiny Misadventures, the Interactive text story chapter 22 by Calvitonks

What follows is a rather interesting journey for you, for your only experience traveling on the floor of a building since you were shrunk was those ruins where you learned spells. Compared to them, this entire apartment was way smaller but in far better condition, with all the rooms and their furniture in pristine condition. 

These two girls are diligent when it comes to the maintenance of their home, for you find little dust and dirt wherever you go: only on the most hard-to-reach corners and spots is any proper amount of them, and even then, there is little to provide shelter to any bug that might scurry around. Therefore, these girls make it a lot safer for your travel, as you do not find any bugs at all. 

While you travel across the rooms, you can feel from time to time the gaze of one or both of the giantesses, who currently are chatting while they eat dinner together at the main table, as they tend to do whenever the two are present at their home at the same time; you turn around and wave at them as signals that you're ok, acts that make Shina visible giggle; she appreciates that her pet keeps his part of the bargain, constantly walking where he is fully visible wherever possible. 

Meanwhile, Kat just looks over, smiles at you before focusing back on her conversation with your owner: you cannot clearly hear what exactly they are talking about, but you suspect that the two are chatting about you and your interactions with your owner, if the red blushed face of Shina followed the friendly gestures of assurance from Kat is anything to go by. There are times, however, when you just stare at them from a distance, allowing you to see a side of Shina that you normally don’t see, letting you further learn that her gentle and friendly interactions also extend to her normal acquaintances, allowing her to quickly earn new companions, something that could prove very useful in the future.

This goes on for the rest of the evening until you're certain that there is not a single uncharted corner of the apartment: the ghost is nowhere to be found, but that’s likely simply because he’s not present at this time of the day, as you assumed from his previous message to you. You approach your owner, trying to get her attention. Once you do, you say:

"Hey, Shina, I found something, a weird piece of scrap metal: I promise to return it to you as soon as I can shape it into something presentable, as my gift for how you have taken care of me." 

"Aww, thanks, little guy! I can't wait to see what my little pet can offer me. Again, just be careful!" says Shina, squatting a bit to be able to reach to pat your head.

Meanwhile, Kat just looks, bemused as to the degree of autonomy Shina is willing to provide her pet. 

Soon enough, Shina stands up and goes to bed. Her roommate followed shortly after.

Darkness begins to rise, and you go to a special spot you found underneath the couch in the TV room: there, with some small wooden fragments and wool treads you built before what you could call a small bed, where you lie to rest until later.

It is hard, and not because of the material: a part of you finds it hard to accept the need to lie to Shina, even though it was a lot more believable than the "hey, I need to talk to a ghost" deal. 

Yet, you accepted it eventually, allowing yourself to rest until the right time.