Each clue can be answered by a long word built by sticking one of the Insides inside one of the Outsides, then adding an extra letter (always immediately before or after the inside):
| Clue | Answer | Outside | Inside | Extra Letter |
|---|---|---|---|---|
| "A ____ Named Desire" | STREETCAR | SCAR | TREE | T |
| Sure bets | CERTAINTIES | CERES | TAINT | I |
| Aid when searching in the dark | FLASHLIGHT | FIGHT | LASH | L |
| Ruin | DEVASTATE | DATE | VAST | E |
| Special someone on February 14th | VALENTINE | VANE | LENT | I |
| Seemingly | APPARENTLY | APTLY | PARE | N |
| Father's new wife | STEPMOTHER | STEER | MOTH | P |
| Fully assured | GUARANTEED | GUARD | ANTE | E |
| Thought about | CONSIDERED | CORED | SIDE | N |
| Horned dinosaur | TRICERATOPS | TRIPS | ERATO | C |
| Monarch | SOVEREIGN | SIGN | OVER | E |
| Creedence ____ Revival | CLEARWATER | CATER | LEAR | W |
| Laws, collectively | LEGISLATION | LEGION | SLAT | I |
| Harmful, as to one's health | DETRIMENTAL | DENTAL | RIME | T |
| Practice for a performance | REHEARSAL | REAL | EARS | H |
| Suggestive (of) | REMINISCENT | RECENT | MINI | S |
Reading the extra letters spells TILE IN PENCE WITH S. Putting TILE in PENCE and adding an S yields PESTILENCE.