“Redundancy is the enemy of efficiency” barks Mike Cruz (Bobby Cannavale), a corporate doctor looking to meddle All Saints Hospital to profitability as part of the overriding arc for Nurse Jackie’s newly premiered fourth season. It’s also the enemy of good television, too. So many once mighty series charge out of the gate at a gallop, only to stagnate after a few seasons, endlessly repeating the same story beats over and over (Rescue Me, Californication, Heroes, etc.), their quality fixed on an uninterrupted, downward trajectory.

Thankfully, it’s a trend the showrunners of this blackly comic dramady starring Edie Falco, about a fatally flawed nurse addicted to painkillers, are taking steps to avoid. For three seasons now we’ve explored every facet of Jackie’s rigidly compartmentalized, plate spinning, life of a functioning addict as she desperately tries to hold onto her secrets while trying to prevent her life from spiraling wholesale out of control. We’ve been privy to her lies, gasped at the level of her manipulation, and been shocked at her callous willingness to see other people pay for her mistakes. Time to move things along.

What makes Nurse Jackie so very clever, and such compelling television is the manner in which the showrunners presented us with one character – a karmic good-fairy, seemingly intent on righting wrongs – and then pulled the rug out from under us so gradually that we almost didn’t notice until we were flat on our backs. The big reveal, as Jackie’s mask slowly began to slip, was that her mischievous antics came not from a sense of decency but self-loathing, as she was shown to be as rotten and as selfish as those who so frequently drew her ire.

Now her secret is well and truly out and with best friend O’Hara (Eve Best) done enabling her, boss Akalitus (Anna Deavere Smith) too preoccupied to cover for her, and onetime lover Eddie (Paul Schulze) no longer prepared to stay silent for her, Jackie's arsenal of allies have finally had their patience exhauted. To rehab then, where Jackie will be forced to confront her vast array of indiscretions with clear eyes and no numbing, floating sensation to soothe her guilt. What happens then is anyone’s guess?