If you are after six interlinked adventures set in the Lonely Mountain area which concern the Dwarves of Erebor and the Men of Dale, this is the book you want (you might alsp want the Erebor supplement, but it isn't necessary). The adventures can stand alone or you may prefer to make them a plot arc within your campaign, starting in the year 2956. With Smaug dead, there's a new air of hope in the region and this doesn't suit Sauron one little bit, especially with that meddling wizard Gandalf interfering... so he has hatched another plot. These adventures are all about thwarting various aspects of his latest scheme.
We learn of some of the key players behind these schemes and a bit more about the overarching plot... but if you want to run the adventures as stand alone ones, that's perfectly possible too. The party may never see the full picture, but they'll certainly have an influence on affairs nevertheless. There are suggestions of how to weave the adventures into your campaign, particularly if you intend to run all of them... and then we're off!
It all begins with The Silver Needle, where the party gets a chance to thwart some bandits who want to steal a wondrous artefact that's in Dale. But what are those orcs up to? Investigation proves it's a bit more than a simple heist... but it all begins with a traffic accident that throws chance travellers together as they wait for the obstruction to be cleared. Various individuals are introduced to give colour to the scene, and there are suggested topics for conversation that make the scene come to life, and may provide useful information as well. In due course, the party can attempt to seek out a bandit leader called Longo who has been plaguing the area, if they don't decide to do so themselves, someone will ask or even hire them to do so. A journey over inhospitable ground and even a swamp ensues... and so does a good scrap, during which they'll find out who Longo actually is. Back in Dale, things are coming to a head as his heist is concluded successfully and it's up to the party to do something about it!
Next comes Of Hammer and Anvils, where Bain himself needs a hand. It all begins in Dale and indeed most of the action is there although it eventually leads to Erebor. Poor Balin is attacked and the party gets the chance to save him. It appears that there's a concerted effort on his life, because he is attacked again, successfully. There's a conspiracy in progress, and the party can investigate... but every decision has consequences.
In Dungeons Deep throws the party into a potential quarrel between Erebor and Dale. It's all down to some long-lost treasure that's come to light, but it all begins with a missing scholar, who the party are asked to find. This adventure is a good one for making contacts with significant individuals, but there is plenty of combat as well, never fear, even though the final resolution takes place in a formal council meeting in which the party will be expected to participate. Then, in Sleeping Dragons Lie, the party ends up dealing with one that most definitely isn't asleep, but is annoyed and about to wreak destruction on Erebor. The party is commissioned to slay him before he can cause much trouble, however they have rivals in their quest... and there's other odd stuff going on as well. Watch out for the moving stones! There's an excellent climatic battle scene to round this adventure off.
Next, Dark Waters sees the party in Lake-town preparing to enjoy the festival of Dragontide. But the sculptor of a statue of Bard that is to be unveiled has gone missing, and his apprentice asks the party for their help in locating him. There's a lot of investigation, as one might imagine, but the party will findthemselves fighting for their lives as well. Layers upon layers mean that several people will have to answer for their actions - if they survive long enough.
Finally matters come to a head in Shadows in the North. Balin is warning of trouble, but is himself under the influence of malign forces. Danger is everywhere and the party needs to prioritise their response. By the end many personalities (who the party will have met if they played all the adventures) will have revealed their true colours and, hopefully, be brought to an accounting. The hand behind all the plots is revealed and the party has a chance to put paid to the entire plot. This is quite an edge-of-the-seat adventure, everyhting piling up at once and needing to be dealt with.
This is an excellent plot arc, exciting and meaningful and would make a good centre to a campaign, or a fascinating thread running through a campaign, as you see fit. Save the world from Sauron. Again.