Children's Suspense/ Thriller. I don't remember much but the ending is they got separated in the tunnel because of the cattles, to be never seen again.

[Llyr]

I read it maybe around 2004 or so. It is written in English. It has a dark cover with some green on it, and i think the title is one word only.

[Rainbowheart]

Who is "they?"

Could you explain more about the ending? Who was in the tunnel and why were they there? How were cattle involved?