I'm looking for an idiom that means something like "making something too obvious", specifically hinting at an event in the future in such a way that it spoils the surprise. "Spelling something out" is very similar, but not quite the idiom I'm looking for. The context I'm using it in is describing a badly-written plot twist, where the foreshadowing was so obvious that it ruined the twist itself.
It's on the tip of my tongue, but I can't seem to find it. Any help would be greatly appreciated!