Once on Hope Island they find the building, but it is surrounded by mines. Slowly making their way through the minefield, they are able to infiltrate the building, finding skeletons of the adults who must have died there.
Unfortunately in their quest for answers, they set off an alarm system and have to quickly escape as a countdown ensues.
They make it to mainland, only to turn and see the building blow up.
Hope Island is named so because it once housed a prison.