When the WB closed down into what's now called the "CW", the newest network wanted successes badly. On Thursday night the WB had some success with two shows, "Smallville" and Supernatural tv show and the CW weren't about to lose either one of them to a different network. The newest executives in the CW gave the greenlight for the two shows to work as the main for their new network that was fighting. They made the right choice as it turns out, because both shows are the sole ones anybody looks to watch on the CW except for "America's Top Model", as well as the evaluations for that show have gone down appreciably this season.
They're just built with a classic muscle car and a couple of weapons to do all their devil hunting after bloody week in week. They do have a few of new buddies to help them along the way, the most notable new buddy being Bobby Singer (Jim Beaver of Deadwood acclaim), who observed the killing after which reincarnation of Sam on one of the final episodes of this season. He understands that his child brother was being too protected by Dean by selling his soul to a female devil to bring his dead brother back to life. Bobby actually needs Dean to maintain killing various vampires along with other creatures of the night for quite some time to come, but now that Dean has sold his soul to this female devil, before Hell comes for him, Dean has just one year to live.