True Bromance is the last of the Lenny and Carl level 27 quests (you can see the others on the Walkthroughs page). It is also the shortest, at least in the number of steps involved.

When we left Carl, he was moving in new social circles and socializing with Burns, Smithers, and Kent Brockman. But he gradually comes to the realization that there’s something missing in his life.

1. True Bromance Part 1 Homer and Lenny should have been free at the end of Carl’s Rise Up the Ladder so that the bromance can begin:

Carl: Homer, please, call me Mr. Carlson
Homer: Uh, yeah. Have you seen Lenny lately? ‘Cause if not, I have him right here.
Lenny: Hey guys, thanks for agreeing to meet me. I’d like to offer you a great opportunity to give me money. I need it to buy back my freedom from this guy I met in prison.
Carl: Jeez, Len, you don’t look so good. Or act so good.
Lenny: I’m trying to outrun the inescapable feeling of failure and disappointment. WHAT’S THAT BEHIND ME!?
Carl: I think you need to rest, buddy. And I need to think some things over. Soberly for a change.
Lenny and Carl go on a simultaneous task – Carl to meditate on his choices at the Buddhist Temple (4 hours) and Lenny to crash there as he still has no money and no home (12 hours). Keep Carl free as Lenny finishes his part of the task.
2. True Bromance Part 2 Carl has come to a decision…

Carl: Excuse me, Mr. Burns. I was wondering if you could find it in your heart to hire back my good friend Lenny Leonard.
Burns: In my heart? Ho-ha, what a delightful jape!
Carl: Please, sir. Couldn’t you just pay me less, and use the money you save to hire Lenny?
Burns: But if I paid you less, you wouldn’t be making more money than you deserve… which means you could no longer be an executive.
Carl: Then I guess I’ll just go back to my old job.
Burns: Very well. Your compassion has taught me something… why I am ludicrously rich and you are middle class. You and your friend can have your menial, nuclear energy jobs. Now let your dainty sentiments never poison my ears again.
Lenny and Carl both go and do a shift at the Power Plant (16 hours).

That just about ends the quest and the lenny and carl storyline – except for a plug for the newest premium decoration that comes as the shift ends:
Lenny: Carl, you got me my old job back! You are the truest of true pals – it’s times like these when I wish we could do more than bro hug.
Carl: I realized I needed you, Lenny. Standing next to you is the only way I look relatively attractive.
Lenny: I wish there was some disturbingly grandiose way to show you my gratitude.

Of course there is – but it costs 120 donuts…