What is the fine-grained topic of the following text: In the midst of this, their classmates (again, I think) comprising of Terk, Moowan, Mon, Newton, Pond, Fern, Meen (Thanabodee Jaiyen, Purim Ratanaruangwatana, Nattasit Kotimanaswanich, Atikhun Adulpokatorn, Manapat Techakampu, Thanyawee Chunhaswasdikul, Anongnart Yusanont) get somehow entangled in their affairs when a mysterious girl Nid (Ploy Sornnarin) appears, along with ghostly sightings of the rumoured missing Siam Square girl. Only return the topic.
The entanglement of classmates in mysterious occurrences involving a ghostly girl sighting.