A quick look back at Baccano! Volume 3,  introduced the Rail-Tracer, Szilard Quates (an immortal alchemist who is searching for the recipe of  Immortality) has appeared to have eliminated most of the Camorra group in the U.S, and Ladd Russo has been thrown off the train with his fiancée.  

Baccano! Volume 4 starts off with the Rail-Tracer and the girl in the black dress (Chane Laforet) on top of the train.   The Rail-Tracer starts talking to Chane, asking about who she is.  He finds out that she is the daughter of Huey Laforet, the one who is currently the one who know the most about the secrets of immortality.  But then, there's a twist!  The Rail-Tracer declares love for Chane, by offering to marry her!  In the meantime, Jacuzzi Splot's and Nice Holystone's group of misfits steals cargo from the train and escapes by jumping into the river, but Jacuzzi suffers some serious injuries.  There's another thing, Chane has also jumped off the train into the river, after carving her answer to the Rail-Tracer's proposal into the top of the train.

Then it goes back to Szilard Quates who is about to kill a fellow Alchemist (Maiza Avaro) in order to get more of the recipe.  Unfortunatly for Szilard, those people he thought were dead in the speakeasy, had all had some of the immortal elixir.  So, they come to save Maiza, and the one leading them is Firo Prochainezo.  Firo is instructed on how to "Eat" Szilard, and thus Firo gains all the knowledge Szilard knew.  These are the two major events that gets volume 4 going.

By the end of this volume, the Rail-Tracer, Vino (Claire Stanfield was his name given at birth, Vino is the name he's given himself), has caught up with Chane, and Jacuzzi has declared Chane a member of their gang.  Then the new suspicion that Ladd Russo is actually alive, and his faithful follower is out to get revenge on the one who hurt Ladd.  As for Maiza and Firo, well, lets just say they're taking a break from mafia activities.

Episodes:

13. Both the Immortals and Those Who Aren't sing the Praises of Life Equally
14. Graham Specter's Love and Peace
15. The delinquents That Arrive at the High-Class Neighborhood Are the Same as Always
16. Carol Realizes That the Story Cannot Have an Ending

Extras:

Baccano! Volume 4 has textless songs, trailers, and actor commentary, which was average for actor commentary, interesting, but I heard nothing that I found exciting.

Overall:

Baccano! Volume 4 has very little blood, compared to the previous volume.  The plot and story starts to come together nicely, and make perfect sense.  Also, this volume seems to be a break for the side of the Mafia that we normally see, and instead, the watcher sees the side of these low-lifes that is human.  The characters develop relationships with each other, everlasting relationships bound by true love.  Lovey-dovey right? Well, not much, there one times it's really mushy, but it's a flashback, and not the prettiest time in Jacuzzi's and Nice's past.  All the other times were either during a fight, or at least there is an explosion.  There was one random moment that didn't seem to belong, where it's suddenly 2002, and you don't know that's the end of the episode.  So basically there was a really confusing transition from episode 13 to episode 14.  Other then that, Baccano! volume 4 is the best in the Baccano! series so far, and I can't wait for the next volume to come out!

Comicsonline gives Baccano! Volume 4, 5 out of 5 Domino Game pieces.