[s12e4] The Tam Turbulence Instant

When Tam reaches out to Sheldon after 20 years because he is visiting Caltech with his son, Sheldon is visibly upset. He reveals that Tam has been on his for decades.

: The episode highlights how much Sheldon has grown and the value of his current "found family". Subplot: Meeting Anu [S12E4] The Tam Turbulence

While the guys deal with Tam, Penny and Bernadette take Raj's fiancée, , out for dinner. "The Big Bang Theory" The Tam Turbulence (TV Episode 2018) When Tam reaches out to Sheldon after 20

: When Sheldon was accepted to grad school at Caltech, Tam promised to move to California with him and be his roommate. Subplot: Meeting Anu While the guys deal with

: The group tracks Tam down on campus, only to find that Tam has no idea why Sheldon is angry. The Truth: A Promise Broken Sheldon eventually reveals the source of his grudge to Amy:

: Sheldon eventually visits Tam in his office and "forgives" him, though Tam remains hilariously confused about the severity of the grudge.

: Sheldon's friends (Leonard, Howard, and Raj) are shocked to learn Sheldon had friends before them.