This is very cleanly written, I found nearly no mistakes, the "how" in para 5, the "at" in para 15 needs to be capitalized "At first. . .", "uncle" when referring to "Uncle Peter", etc. . ., but nothing of real note. It seems like it could be a very interesting story.
I do have a couple of criticisms, though. First, it is very short. The description says that it's chapter 1, but it is too short to be a chapter. Yes, I know, there are many shorter chapters out there in the literary world, but this is short by conventional standards, and, if you're looking to get published, conventional standards are your friend.
Second, it is a little bland. The subject is good, probably exciting even, but the piece doesn't really convey that excitement. Maybe a little more description would help, describe the room they're in, their clothes maybe. The dialogue is well written, maybe you could give some more detail about their expressions? I suspect Uncle Peter would be a little more annoyed about being dismissed so summarily after bringing Liam something he clearly thought was very important.
Overall, I think it has a lot of promise. Good job!