Hawaii Five-0: Hana Komo Pae

SYNOPSIS

When Grace goes to her Winter Formal, Danny offers to chaperon because he wants to know who her date is. When he discovers who it is, he takes him to the bathroom to talk. It's while they're in there that some men with guns come in and take everyone hostage. Danny stays hidden. He can't call anyone because they jammed the cellphones. Eventually Danny confronts one of them and the one he's with thinks he knows why they are here. Grover goes to check on his son who is also there but the guy on the outside won't let him in. But Grover insists on going in that's when he pulls a gun. Grover then calls Steve to come. They eventually find out what's going on and realize they have to go in but they need to know who they are and where they are. The people inside learn about Danny and threaten Grace unless he surrenders which he does.