Konosuba: Even More Explosions on This Wonderful World!, Vol. 3 (manga)

After pulling off her first heist with the thieves she so admired, Megumin settles down and goes back to being a normal member of Kazuma’s party. Yet somehow, she finds herself dragging Yunyun to the castle where “Illis” (aka Princess Iris) resides. Ostensibly, she's come to invite Iris on an adventure... but what are her true intentions?!