Rookie Blue returns to both ABC and Global on May 23, though the summer series with which many fans have fallen in love will look very different next month.

Andy is back from her undercover mission. Sam is now a detective. And he has a new girlfriend. Eek!

Elsewhere, Dov's one-night stand will cause problems for him at work, while Chris has a major decision to make and Traci is discovering how to live without Jerry.

Watch the first official Rookie Blue Season 4 trailer now and prepare for a series of changes at work and at home for members of this precinct:

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.