Spoilers

[serojay]

Months after explosions brought down Pinehearst and Primatech, our Heroes try to put the past behind them and begin new lives. Now powerless, Hiro (Masi Oka) tries to train a reluctant Ando (James Kyson Lee) to be a true superhero. Suresh (Sendhil Ramamurthy) returns to life as a taxi driver, Peter (Milo Ventimiglia) is back to saving lives, and Daphne (guest star Brea Grant) and Matt (Greg Grunberg) try to live as a normal couple. Claire's (Hayden Panettiere) attempt to live a regular life is cut short when she uncovers a deadly plot orchestrated by Nathan (Adrian Pasdar) to track down and capture those with abilities. Meanwhile, Sylar (Zachary Quinto) begins the search for his real parents. Jack Coleman, Ali Larter and Cristine Rose also star. Ntare Mwine guest stars.

[serojay]

Source: http://heroesspoilers-odi.blogspot.com/2009/01/new-volume-details-and-promo-pics-in-tv.html

The following was printed in a tv mag.

1) A body of a MAJOR character has an axe in the back of their head and is zipped up into a body bag
2) In Episode 3x14 - It is indeed weeks after the Volume 3 finale and the Heroes are struggling to get back into their daily lives, Peter as a paramedic, Mohinder as a Taxi Driver, Matt as a bodyguard, Tracy with the Gov, and Claire is with Angela trying to get into college.
3) The Hunter is sent by Homeland Security to track the Heroes and death is an option
4) Sylar teams up with The Hunter after being initially hunted as well
5) Tracy is kept captive under heat lamps
6) The Hunter's name is Danko
7) HRG will work on "both sides of the fence" to survive
Sylar's father is a taxidermist and his first meeting with his dad is not what Sylar expected and sends him down the vil path again
9) Dan Byrd's character joins Sylar on a "twisted" road trip

[AEYH]

I like the Trcay and heat lamps idea.

[doctor70094]

01/30 - Months after explosions brought down Pinehurst and Primatech, our Heroes try to put the past behind them and begin new lives. Now powerless, Hiro tries to train a reluctant Ando to be a true superhero. Suresh returns to life as a taxi driver, Peter is back to saving lives, and Daphne and Matt try to live as a normal couple. Claire's attempt to live a regular life is cut short when she uncovers a deadly plot orchestrated by Nathan to track down and capture those with abilities. Meanwhile, Sylar begins the search for his real parents. Jack Coleman, Ali Larter and Cristine Rose also star. Ntare Mwine guest stars. Source: NBC

10/27/2008 - Zeljko Ivanek will be joining the gifted ones as a character called "The Hunter." According to E!, Ivanek will arrive in episode 14, which is the first of Volume Four: Fugitives. Source: TV Guide Online