Post ME2: Arrival + NPCs
After the events of the Arrival DLC when the truth of the Reapers comes to light, the Council strips Shepard of her status and rank and puts her under essentially house arrest, not letting her leave Earth space at all. This is due in part to the destruction of Batarian colonies, but that’s a cover for the fact that they refuse to listen to her about the coming of the Reapers.
During this six month period (until the events of ME3), she is confined to her living quarters on her home military base. People still seek her out for some training or to have a drink or two with her, maybe get lunch or dinner. She becomes acquainted with a small squad that’s progressing quickly through their ranks and proving themselves a force to be reckoned with. This squad* includes Skylar (vanguard, their leader), Emma (soldier, weapons expert), Gary (nickname, Krogan warlord), and Bethany (Engineer, tech specialist).
They all become good friends with Samantha and she comes to rely on them throughout the events of ME3, finding them to be among her most trusted allies.
*These squad members were character my friend and I played in the multiplayer and ended up fleshing out into OCs. There’s several others, all of whom I love, but these are the ones that might be referenced post Arrival.