What Happened at Midnight
| Publisher | Grosset & Dunlap |
| Publisher Series | Hardy Boys Mystery Stories |
| Series | The Hardy Boys |
| Format | Hardback |
| Language | English |
| Location | USA |
| Copyright | 1931 |
| Pages / Font | 213 pages |
Added by jlkrien · Last edited by Anaideia
| Publisher | Grosset & Dunlap |
| Publisher Series | Hardy Boys Mystery Stories |
| Series | The Hardy Boys |
| Format | Hardback |
| Language | English |
| Location | USA |
| Copyright | 1931 |
| Pages / Font | 213 pages |