Within the Grip tells the tumultuous story of Gu Yu Luo, raised by the influential Gu family and destined to marry Gu Chao Xi. As Gu Chao Xi prepares to lead the Xuanji Pavilion, he is suddenly assassinated. To preserve stability, Yu Luo desperately seeks out a look-alike to train and install in his place. Meanwhile, Crown Prince Yin Zhou discreetly investigates the Gu family, publicly presenting a gentle facade while operating ruthlessly behind the scenes. His inquiry uncovers a shocking truth: Yu Luo's actual husband, Gu Chao Xi, is his long-lost elder brother. Both burdened by their own secrets, Yin Zhou and Yu Luo initially find themselves at odds. Yet, amidst the perilous circumstances, their relationship evolves, leading them to gradually develop deep feelings, mutual understanding, and ultimately, a shared love.