10 : A Sound Argument -

: A small-scale display of the Wall Titans' power to deter world invasion.

The "sound argument" of the title refers to the cold logic that sacrificing one individual (Historia) is a necessary evil to save the nation. 10 : A Sound Argument

If you are referring to the episode " A Sound Argument " (Season 4, Episode 10), it is a story centered on the heavy burden of duty and the erosion of hope. : A small-scale display of the Wall Titans'

: In the present day, we see the tragic outcome. Historia is shown pregnant and despondent, seemingly having accepted a fate she never wanted. 10 : A Sound Argument