system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars] Darth Vader decides to go for a walk through the Tantive IV and finds his two old droids trying to get into the escape pod. He catches them and views the transmission from Princess Leia revealing Obi-Wans survival? What happens next.
gpt
He heads down to Tattooine to hunt Obi-Wan, using the coordinates programmed into the droids as a starting point.

There's a few options at this point. 

* He searches, but Obi-Wan realizes he's being hunted and remains hidden. Vader eventually is forced to give up the hunt, coming to the conclusion that Leia must have simply been mistaken and Obi-Wan is dead. Beru and Owen are never killed, Luke never leaves to join the rebellion, the Death Star wins.
* He locates Obi-Wan. They fight, Vader wins. Beru and Owen are never killed, Luke never leaves to join the rebellion, the Death Star wins.

Those are the boring options. But wait, there's more...

* He begins his search near one of his only points of familiarity: The home of his step-brother, Owen. He discovers Luke, and realizes the true nature of their relationship (Luke calls Owen "uncle", Luke's last name is *literally* Skywalker, whatever). Whether or not Obi-Wan intervenes or not is irrelevant, because Vader would kill him if he tried it. In either case, Luke is captured and trained as a Sith in secret by his father. Together, they attempt to overthrow the Emperor. But Sheev isn't stupid, sees it coming, and kills both of them. He trains up a new apprentice. 

No matter how you look at it, if Vader goes to Tattooine to search for Obi-Wan, it's game over for the rebellion and the galaxy.