Belly of the Beast

Belly of the Beast is a main quest in Fallout 76.

Quick walkthrough

 * Use four Brotherhood emergency transponder radios to find Elizabeth Taggerdy's location. Game doesn't checkpoint radio progress, so if logged out, likely will have to start over to maintain radio progress until get inside cavern for location guide to Taggerdy (large cavern).
 * Head to and enter the glassed cavern.
 * Traverse the caverns towards the last transponder radio.
 * Kill the scorchbeast blocking the last transponder, if necessary.
 * Use the last transponder next to Taggerdy's body.
 * Pick up Lieutenant Elizabeth Taggerdy's ID from her corpse to access the information on her terminal. It can also be used to access the elevator outside the Asylum if the player character doesn't have their own military ID.
 * Get out of the Caverns and head back to Fort Defiance. There is an exit near Taggerdy to leave the caverns.
 * Use Taggerdy's terminal to learn more about the Scorched, scorchbeasts and ultracite power armor.

Detailed walkthrough
This quest consists of five transponder beacons that put the player character in the footsteps of Elizabeth Taggerdy, ultimately leading them back to Elizabeth Taggerdy's terminal at Fort Defiance. Progress from beacon to beacon is not saved if one disconnects, but it is possible to start the quest at any beacon. It is not necessary to start from the first.

Beacon 1 is located on the road between Fort Defiance and Watoga. Be prepared to battle Scorched, mirelurks, cave crickets, robots or some combination thereof. Approach and interact with the transponder relay to listen and acquire coordinates of the next beacon.

Beacon 2 is located in Watoga, by the crashed vertibot in front of AMS corporate headquarters. Be prepared to battle robots and Scorched. Approach and interact with the transponder relay to listen and acquire coordinates of the next beacon.

Beacon 3 is located at Survey camp Alpha. Be prepared to battle Scorched and a scorchbeast. One may need to repair the automated surface to air missile that will attack the scorchbeast and the Scorched. It may need to be repaired during the battle. Approach and interact with the transponder relay to listen and acquire coordinates of the next beacon.

Beacon 4 is located at Drop site V9, on top of the bunker. Be prepared to battle many Scorched. Approach and interact with the transponder relay to listen and acquire coordinates of the next beacon at the glassed cavern.

Beacon 5 is located in the glassed cavern. This is a major undertaking. While progressing through the cavern, one should be prepared to battle Scorched, mirelurk kings, fog crawlers, and, when approaching the last beacon location, a scorchbeast. Approach and interact with the transponder relay to listen and acquire the final location for the quest. Take the elevator to the surface and proceed to Elizabeth Taggerdy's terminal in back in Fort Defiance.