Here's what's gonna happen on Melrose's new season:
Linden Ashby arrives in town. He portrays Dr. Brett "Coop" Cooper. He has a mysterious connection to the late Dr. Kimberly Shaw, which we'll learn in the season premiere. He befriends Michael and Peter. His ex-wife Lexi Sterling (Jamie Luner) comes to town (in 4th episode) to settle their divorce.  She comes armed to audit his bank account and there is gonna be a fight.  She may be a love interest for Peter. Why?
Peter, now that he knows of Michael & Taylor's scheme, will ask Taylor to marry him. He thinks Taylor's pregnant with his child. At the alter, though he calls her "a scheming slug". Taylor will try to get Michael to impregnate her as their scheming continues. They find out they have an affinity for each other.  Megan, in the meantime, takes matters into her own hands. Megan will find happiness on her own, and at that point tries to control the situation between Peter & Michael. Also, Michael's hands are badly shattered after Peter threw him through that glass window. 
The hatred between Samantha & Craig really heats up. Craig despises Samantha for running over and killing his wife, Sydney. Jim, Samantha's father, dies as a result of the car crash.  A funeral is held for Sydney at which Craig expresses his hate toward Samantha. Her & Billy go through some personal problems as well.
Jeffrey Nordling is another new person who arrives in Melrose Place. He plays Eric, a powerful man from Amanda's past.  He pops up in the season premiere and then in episode 3 + he sticks around after that. He is the one who promoted Amanda from an assistant to an account executive. She moved to the west coast, but they've kept in contact all this time.  
Amanda will be busy re-evaluating her life. D&D is gone, so she will start her own agency. They're will also be interesting things going on between her & Kyle, now that they've slept together. 
Kyle will have his hands so full with Amanda & Taylor that he won't have time for Jennifer, who has been going after him. Jennifer will  go after  widower Craig Field, who will need a shoulder to cry on.