Dex faces off against Artie Banks to take down wealthy real estate mogul Randall Tapper. Meanwhile, Detective Cosgrove leads an investigation to find Wallace Kane, a prisoner on the loose.

Despite being ordered by Lieutenant Cosgrove to take time off, Hoffman enlists Dex’s help to investigate a case. Meanwhile, Tookie’s culinary skills come in handy at Bad Alibi, and Dex stresses over an interview to become a certified PI.

When Dex’s ex Fiona, a famous musician, comes into town for a performance, Dex must protect her from a stalker. Meanwhile, Grey continues to receive the cold shoulder from Dex, and Tookie and Lieutenant Cosgrove develop a new friendship.

Dex goes undercover as a high school substitute teacher after an old classmate of hers enlists her help to find out who planted drugs on her daughter. Meanwhile, Dex and Liz’s relationship gets too close for comfort.

Dex goes under cover as a potential buyer to help Hoffman and Grey with the next phase of their drug case; Dex becomes close to a fellow veteran support group member; Ansel struggles to maintain order at Bad Alibi and enlists Tookie's help.

Dex is hired to investigate a bride’s fiancé after suspicions arise regarding the motives behind the hurried nuptials. Dex asks Hoffman for help with the case and discovers there’s more to this couple than meets the eye. Meanwhile, Hoffman goes head-to-head with his father when he learns that he will be representing a suspect in Hoffman’s case. Back at The Bad Alibi, Tookie and Ansel propose a new business idea to a reluctant Grey.

Dex takes on a new case helping a mother who has lost custody of her children, which triggers parallels to her time in Afghanistan. After memories of Afghanistan reemerge, Dex spirals and must face the reasons behind Benny’s death. Back at The Bad Alibi, Grey and Tookie coach Ansel on how to ask a girl out on a date.

Dex’s former client Jeremy introduces her to Major Elders who has intel on Benny’s death. Dex, suspicious of the information and looking for answers, investigates a potential cover up involving Benny’s unit in Afghanistan. Elsewhere, Hoffman and his partner, Lee, work closely on a sting operation which shockingly involves a familiar face. Meanwhile, Grey’s newfound relationship with his father is tested.

To get justice, Dex takes matters into her own hands after finding herself at the forefront of a murder investigation where she’s the prime suspect. Meanwhile, Hoffman struggles to remain impartial in the investigation and could lose everything if he continues to help Dex. Elsewhere, Grey attempts to work on his budding relationship with his estranged father while a familiar face from the past makes a surprise visit. Season finale.