Guess Who I Saw Today

 is a quest in Fallout: New Vegas.

Quick walkthrough

 * 1) Go to Jacobstown.
 * 2) Speak with Doctor Henry.
 * 3) Head to Charleston Cave.
 * 4) Retrieve the Chewed Stealthboy.
 * 5) Return to Doctor Henry.
 * 6) Talk to Lily Bowen.
 * 7) Deal with Keene.

Detailed walkthrough
To begin the quest you must go to the Jacobstown Lodge and talk to Doctor Henry and tell him you will help him with a problem.

Meet with Lily, a smaller Nightkin standing by the pen outside the front of the lodge after accepting the quest. You can invite her to come with you, but do not have to (This will only work if you do not have a fellow humanoid companion already).

Exit Jacobstown and circle around to the Northwest to locate Charleston Cave, and enter. Continue through the cave following your compass (generally moving downhill) while dispatching Nightstalkers and eventually you'll come across a couple of Bighorner bodies and a Nightkin body, with Oh, Baby! next to it. Examine the Nightkin and take his Chewed Stealthboy and you'll be prompted to return to the Doctor Henry back in the Jacobstown lodge.

Back at Jacobstown, talk to the doctor. He'll inform you that the Chewed Stealthboy may be a breakthrough in his research and that Lily is his best experimental subject. Talk to both the doctor and Lily, they both will agree to the experiment. It's a success, but as soon as the doctor is finished Keene enters the room and demands the Stealthboy Mk. II specs.


 * If you can pass a speech check (80), Keene can be spoken down.
 * If you give him the specs he'll leave.
 * If you don't give him the specs, he and two other Nightkin will attack.
 * You can easily draw the three of them outside and let the Super Mutants help you do your work.
 * You can also go in the corner (where the wheeled tables are) to prevent the Nightkin from attacking you (or delaying them).
 * It is possible to use a Stealthboy and reverse pickpocket C4 onto Keene and his 2 Nightkin before speaking with him. This way, if you chose to fight them, you can use a detonator to instantly kill all 3 at once.
 * Note, Lily will leave the lodge as Keene is coming into the room, she will therefore not help you with the fight**

In the lodge, speak with Doctor Henry again.
 * If you can pass a science check (90) you can convince Henry to test the Stealthboys on Nightstalker brains.
 * You can also inform the Doctor the risk is too great, and Lily should not wear it.
 * You can also tell him you think Lily should continue to wear the Mark II prototype.

Whichever decision you choose, it will end the quest. The outcome of each decision seems to have a different effect on the game although you will always be able to take Lily as a companion ✅. Passing the Science check gives you around 100 more experience than the other two options do. Passing with the science check awards 590 XP.

No matter the outcome, the player will NOT be able to acquire the Stealth Boy MK II Prototype.

Bugs

 * After you've killed them, some of the dead nightstalkers in Charleston Cave are still standing/sitting as if they were alive.(This bug is very common with other four-legged animals/mutants such as: Bighorners, Brahmin, and Vicious Dogs.)


 * For the Stealth Boy MK II test to work properly, Lily, Doctor Henry, and Calamity need to be present, awake and standing/sitting around idly in Doctor Henry's laboratory, Keene should stand in the lobby or nearby.
 * When Doctor Henry isn't idle when you tell him to start the experiment, any AI-command that is currently running (like walking to his computer) will override the AI commands for the experiment-cutscene. Lily will then be stuck in her waiting dialogue, and Henry appears to forget about the experiment.
 * If you manage to get to Doctor Henry before Lily arrives, you can still initiate the test. This will cause Henry to talk to the absent Lily and break the sequence, having Henry standing there unresponsive, waiting for Lily to act.
 * If Calamity is not present there will be a long pause in the dialogue when Doctor Henry asks for the results and Calamity's words will not be spoken.
 * Apart from reloading, there are several methods to make Doctor Henry responsive again, so that at least the quest "For Auld Lang Syne" can be finished:
 * Failing a pickpocket attempt on Henry may reset his AI after he confiscated your stolen goods
 * Waiting for 24 hours may trigger the next stage of the sequence
 * Killing Lily will cause the quest to fail and make Henry responsive again.


 * Keene may become immediately hostile when the test is finished, not even talking to the player. Everyone else in the room may also become hostile when you defend yourself.