"Die Hard in a high school" does pretty much sum it up, but don't let that put you off. It's a thoroughly enjoyable, well written, well acted, well directed movie. The change of setting is indeed a visceral, terrifyingly real world possibility that people can relate to, much as people did relate to terrorist hijackings in the late '80s (and about as many people have direct experience with each - thankfully rare). The scene change definitely puts a spin on the old plot, and it's nice to see a believable female hero, in the way Bruce Willis was very much an everyman, nothing terribly special about him. There's no overt political messaging, don't buy the hype "ooo so scary it's associated with the Daily Wire," whatever. Critics just say that because they'd rather you wasted your time on some drivel like "The Shape of Water."