Why is Frederick “Freddy” Lambert back? ‘Chicago Med’ sees French Stewart reunite with Charles

'Chicago Med' welcomed back several familiar faces in its latest episode. 'Lessons in Chemistry' opened with Charles (Oliver Platt) beside Frederick 'Freddy' Lambert. Fans may remember Freddy as Margaret's fiancé. Margaret (Deanna Dunagan) was Charles' mother, who died back in Season 10, in an episode titled 'The Invisible Hand.' The pair had a complicated relationship. In the same episode, he meets Freddy, played by French Stewart, who was engaged to Margaret. Charles immediately suspected Freddy and began interfering in his case. The psychiatrist wasn't sure of Freddy's intentions towards his mother. After realizing Freddy had no ulterior motives, Charles tried to apologize to his mother, but it was too late, as she had passed away. Freddy was last seen in the following episode titled 'Baby mine...' attending Margaret's funeral.

Freddy is back in the latest episode to sign Margaret's estate papers alongside Charles. During the process, both of them uncover Blackhawks season tickets in an envelope addressed to someone named 'T.T.' Later in the episode, Charles uncovers that 'T.T.' stands for 'Tommy's Team.' It is an organization his mother started after his brother's death. Margaret brought the seats for the organization. The place also carried a plaque dedicated to Charles' brother. Now, Charles faces a tough decision: either continue his mother's wishes or refund the tickets.

This revelation was hard for Charles to accept, as he remembered Margaret as unemotional. The reason they became estranged was that she did not support his marriage to CeCe, an African American woman. She kept her distance for 35 years because Charles didn't give in to her demands. Charles ultimately decides to attend the game with Frederick to experience a different side of Margaret. The episode also brings back Lennox (Sarah Ramos), who was absent for a few days because of a secret drug trial. Ripley (Luke Mitchell) and Lennox pick up where they left off. Elsewhere, Goodwin (S. Epatha Merkerson) uncovers Miranda's illegal scheme, while Wu (An-Li Bogan) friendzones Frost (Darren Barnet). To find out what happens next in Gaffney Chicago Medical Center, tune in every Wednesday at 8:00 p.m. ET (7:00 p.m. CT) on NBC