Stafford's conversation with Grace about her upcoming presentation to earn a fellowship is interrupted when a woman, Casey Lambert, who was struck by a speedboat while swimming, is rushed into the emergency room, where Brett and Grace save her life.
Meanwhile, one of Moretti's thugs watches Constantine pressure Alderman Spence to switch positions and legalize video poker machines in Chicago. Upon hearing this news, Moretti decides to kill Constantine.
Back at the hospital, the speedboat's driver, Seth Ross, tells Grace that he's sorry about the accident and that he has Casey's dog. But when Grace and Brett check Casey's progress, she has no memory of going swimming.
Constantine tells his gang about Spence's change of heart and that Nate - having taken that cop's beating without giving up information - is now an official member of their organization.
Franco asks Grace to meet in the hospital's garage, where Moretti kidnaps her at gunpoint. They drive to an abandoned factory, and Moretti tells Grace to have Constantine meet her there or he'll kill her family. Meanwhile, Seth assures Casey that her beloved dog is OK.
Grace asks Constantine to meet her, but her story is so far-fetched that Constantine orders Nate to determine Grace's whereabouts. Franco later tells Grace that it wasn't his idea to use her as bait.
Meanwhile, Brett's work on his and Olivia's presentation is interrupted by Casey's sudden inability to breathe. After Brett and Stafford perform a tracheotomy, they discover Casey had tapeworms in her lungs.
Later, as Olivia concludes their presentation, Brett - realizing that Grace is absent - tries to stall for time but fails. Stafford orders Brett to find Grace, so Brett phones Nate, saying Grace has been missing for hours and Franco was trying to reach her. Nate - who already knows Grace isn't there - says he'll check their home.
When Franco again tries to apologize to Grace, she knocks him down and runs outside. Moretti shoots her in the leg and sends two thugs after her.
Grace enters another building and eludes the thugs. She then sterilizes a knife, removes the bullet and applies a tourniquet. Meanwhile, Stafford and Brett tell Casey that allowing her dog to lick her face enabled tapeworm eggs to get into her lungs and hatch there. Then they notice her shaky hands.
When Constantine learns Grace hasn't been home and Franco hasn't been making his weekly collections, he decides to kill Franco and Moretti. Nate wants to come along. OK. Moretti's thugs stop searching for Grace and prepare to ambush Constantine.
While Stafford discovers Casey has a cyst on her brain that's filled with tapeworms, Grace limps to an empty guard shack and phones Constantine just seconds before he arrives.
A furious gun battle erupts. Constantine and his men escape, locate Grace and carry her away. Meanwhile, Stafford and Brett remove the cyst.
Safe at home, Grace bandages her wound and saves the bullet. Brett calls, saying Stafford's angry about her missing the presentation and that they need to talk. Grace hangs up.
Constantine tells Grace he appreciates her bravery, adding that Moretti and Franco will soon be dead. Until then, she should get some rest.