Monroe's relationship with Danny Messer was a tumultuous one. Danny initially resented her, since she replaced Aiden Burn, his partner and best friend. When he met Monroe at the zoo on her first case, he told her to call Mac "Sir," to which the CSI supervisor takes offense. Soon after, Danny begins to call her "Montana," initially a pejorative, but it soon becomes a term of endearment, although he eventually stops calling her that. Danny is flirty to Lindsay in episode 2.13 (”Risk”) and also in episode 2.18 and 2.19.