How to Rest is the 9th episode of Hai to Gensō no Grimgar anime adaptation. It first aired March 7, 2016.
Haruhiro and the group take a day off. During dinner, Haruhiro suggests that they change hunting grounds to the Siren Caves, citing increased goblin activity at their present hunting area. Mary, surprised by this, excuses herself and leaves because it is in those mines that she lost her friends to a particularly large and savage kobold named Death Spot. Despite their misgivings and Mary's obvious emotional baggage, they are determined to try it. During a training session with Barbara, Haruhiro asks her about the streaks of light that he has seen while fighting, which seem to show him how and where to strike.
For a day, the party agreed on having a break though Haruhiro seemed to find that it felt odd. Early in the morning, Ranta had gone fishing in a boat by a lake. Moguzo spent his time improving his cooking skills and fixing his armor and sword. Haruhiro had encountered Shihoru on the bridge, which she spent her time overlooking the scenery. He later went to the lodging that Mary stayed in, talking and enjoying a hot beverage with. By this time, Yume was still asleep though afterwards, Ranta caught her climbing a cliff.
As it got to evening, the party met at Shelly's Tavern and discussed the issue of their next mission. Although everyone agreed on going to the Cyrene Mine, Mary wasn't ready and left to catch some air. Haruhiro followed her out and talked with her, which got her to finally decide to overcome the grief of her former comrades. Preparing for the fight, Haruhiro went to learn a new skill from his mentor who teased and somewhat tortured him, asking about his interests in girls.
The next day, they set out for the Cyrene Mine.