From Goodreads: Sep, Arkle, Mack, Lamb and Hadley: five friends thrown together one hot, sultry summer. When they discover an ancient stone box hidden in the forest, they decide to each make a sacrifice: something special to them, committed to the box for ever. And they make a pact: they will never return to the box at night; they’ll never visit it alone; and they’ll never take back their offerings. Four years later, the gang have drifted apart. Then a series of strange and terrifying events take place, and Sep and his friends understand that one of them has broken the pact. As their sacrifices haunt them with increased…