Bye Bye Love

 is a quest in Fallout: New Vegas.

Quick walkthrough
NOTE: The "Bye Bye Love" quest may not be completable due to reported bugs.

A working way to complete this quest is to complete the quest How Little We Know. This is the quest that you start by talking to Cachino. You should not kill him, instead get his help to confront the Omertas. [Edit] Completing "How Little We Know" before completing "Bye Bye Love" will result in FAILING this quest. Make sure to search the bodies of Nero and Big Sal, they contain some quality guns and other inventory.

Detailed walkthrough
NOTE: It seems that there is no way to complete this quest without passing a 50 speech check.

This is a quest that begins in either the Gomorrah Casino or Vault 21. If the Courier goes into the Gomorrah courtyard, Joana will begin a conversation. Passing a Medicine or Speech check will initiate dialog that will eventually have Joana talk about Cachino and Carlitos. Or the player can talk to Carlitos in Vault 21, pass a speech check about why he left Gomorrah and Joana. Carlitos will give the Courier 200 caps upon accepting the offer to help him and another 200 upon completion.

The Courier has the option to help Joana, before or after choosing to have a sexual encounter, by finding Carlitos (located in the diner of Vault 21) or letting her know Carlitos is looking for her. After some running back and forth between Joana and Carlitos, the Courier can agree to help Joana, Carlitos, and two of Joana's girls escape to Freeside; the agreement being to wait until between 12AM and dawn, being Gomorrah's most busy hours, before attempting the escape. Carlitos advises the Courier to get some backup before attempting the escape, as he knows two guns-for-hire that owe him a favor, located in the Atomic Wrangler. The escape itself is literally just walking through the front doors of the casino and out of The Strip.

Once you meet up with the hired guns and Carlitos, 4 Omerta thugs will ambush the group. The player can either go into combat with them or with high enough Strength (8,9) or Speech (85) skill, avoid the fight altogether. After the confrontation, Carlitos will thank the Courier and ask if there is a way to repay the kindness. From here you have a choice between receiving 400 caps or accepting a simple thanks. Alternatively, if you talked to Carlitos first and you have a high enough Barter skill (65), you can get another 400 caps on top of the 200 at the start.

From here, Joana will thank the Courier and mention a sinister plot she's heard about Cachino and the Omertas; the How Little We Know quest will initiate if you haven't found this quest already.

Behind the Scenes

 * The name of the quest is a reference to the "Everly Brothers" song of the same name.

Bugs

 * Due to a glitch, Carlitos isn't appearing in the game for many people, making the quest temporarily unfinishable. To fix this on PC, simply go to the diner in the Vault 21 hotel and use the console command: player.placeleveledactoratme 11f862. This will spawn Carlitos right in front of you.


 * Instead of spawning a new NPC, use the existing one. Type "prid 0011f87a" (Carlitos) or 112471 (Joana) using the refid, then just type in "enable".  It seems something just disabled them.
 * Seems to work much better than using the above mentioned player.placeleveledactoratme method; Quest scripts should work as intended, preventing the problems with not-moving NPCs.


 * Another glitch has risen as Joana seems to disappear too after you talk with Carlitos. To fix the Joana glitch, go to the Gomorrah courtyard and us the console command: player.placeleveledactoratme 0010c6f6.
 * sometimes, Joana is just in the alcove below her room (precisely over her bedroom door) the Quest marker will point to the door making you think she's in the room when you're in the courtyard and she's in the courtyard when you're in the room.


 * Another glitch can render this method useless: spawning Joana in the courtyard makes her disappear once she enters her room (since she tells the player to follow her to her room). If you spawn her inside her room, she keeps asking the player to go to her room.
 * Yet another glitch with this method which can occur and which renders this method useless is that Joana does not lead the way to her bedroom when she is supposed to. Instead, she continues to stand around doing her own thing. Attempting to engage her in conversation will only cause her to tell you to meet her in her room, but she does not budge. This bug is not experienced when Joana is not manually spawned from the console, so it seems there is some script or other NPC behavior not being attached.
 * This glitch will happen on the PS3 if you complete the How Little We Know quest before taking Joana out of the casino.


 * Yet another glitch exists where, after telling Joana the escape plan, she arrives in the lobby of Gomorrah - but does not follow the player. Neither do the disguised hookers waiting outside the casino; leaving to Freeside without them results in failing the quest a few hours later. One solution to this problem is to engage Joana in combat, leave Gomorrah and then go back in and start dialogue with her again.


 * After running back and forth a few times, the dialogue option to get Joanna to run away might fail to appear. The only way around this seems to be to have a high enough speech to convince her.


 * The quest will fail the second you leave the casino.


 * Killing the bosses with Cachino during the quest How Little We Know can cause you to fail this quest.


 * Discovered that the "Bug" that makes either Carlitos or Joana Impossible to find appears if the quest How little we know has been completed. Thus if you completed that quest, then it seems it might be impossible to finish this quest as both main characters is missing and spawning them with a cheat command only takes you to the escape where the quest stops working when Joana wont leave the casino.
 * Can spring up without completing the How Little We Know quest.


 * Upon leading the girls and Joana out the gate to freeside, the Securitrons posted outside the gate can become hostile, attacking all included parties. Killing them would give negative fame at the strip but letting them kill Joana fails the quest.


 * After Joana and her friends are in their diguises: Once the player exits to The Strip the game will permanently lock up once the player tries to move.


 * After leading the girls to Freeside, Carlitos doesn't appear, resulting in the quest being unable to continue as the girls and the Omerta thugs stand around and do nothing. Killing the Omerta Thugs will not advance the quest since the girls are still waiting for Carlitos to appear to advance the quest dialogue.


 * It is possible that if you complete the quest How Little We Know by killing the bosses with the help of Cochino, and have already started the "Bye Bye Love" quest, you will automatically fail the quest.


 * Unfortunately the game does not indicate whether the "Bye Bye Love" quest was failed or completed, despite going into the list of "completed" faded out quests.