The Disabled Tyrant's Beloved Pet Fish: Canji Baojun De Zhangxin Yu Chong (Novel), Vol. 4

STILL WATERS RUN DEEPWith their union blessed by the emperor and four baby heirs in tow, Prince Jing is well on his way to clinching the position of crown prince. But Li Yu can't pat himself on the back for a job well done just yet! Prince Jing's crafty brother still lurks in the shadows plotting against him.
As Li Yu dives deeper into the sixth prince's schemes, he uncovers a dastardly conspiracy that ripples from Prince Jing's childhood, forming a tsunami poised to plunge the imperial palace (and its allies) into total chaos! Li Yu will have to use all the fishy tricks at his disposal if he wants to keep his new family safe!