So new and already changing?

I turned on my tv for a little "Missing" before work and I noticed that EVERY single character except for Jess had been changed?

New partner, new boss, new co-workers.. everyone.

What's going on? Anyone know why all the other characters are gone?

Sunny was just getting through her paranoia problems and Jess was having feelings for that agent, but now they're all gone.. I don't get it!

Anyone know what the hell is happening?

Ps. It was the episode where they have to find a girl who went missing at the mall in an elevator.