Boundless Cultivation - Chapter 58 - How Did You Do That?

When The Cute Kunoichis Spied on Their Teacher's Secret is a light novel written by Kazuma Kamachi and illustrated by Ryuushi Tajima.

The story takes place in a world where Japan never ended their isolationist phase, and agents from foreign powers are always threatening to steal the country's advanced technology. In order to combat this threat there has been a resurgence of ninjas that use Strategic Martial Arts, techniques that combine cutting-edge modern technology with a traditional foundation of martial arts and ninjutsu. The story follows Souha Sugiyado, a 17-year old ninja instructor and former ninja prodigy who was forced to retire from active duty by the wounds he suffered in his last mission. Souha's four students are all kunoichi who have all gained the rank of Elite Ninja, the highest official rank available to ninja. However, one day two Shogunate ninja approach him with the news that his four students have gone rogue and have stolen a portable modular nuclear reactor, and thus they ask for his help in bringing his students to justice.

Xia Ning is betrayed by her boyfriend who wants to marry another girl from a rich and powerful family.

One day, Luo Jian woke up from his sleep and found himself in a locked chamber where the door and window were all sealed. A note with a few lines written on it was tacked to the wall: “Escape from this room within an hour, otherwise, you will die.”

There is a sequel called Reincarnation Night (轮回之夜) that takes place in the same universe but has different main characters

- Description from Novelupdates

Yan Xi was the eldest young lady of Beiqiao City’s top four families, the Yan family. Despite her talents, she was sickly and destined to die young. She was an unattainable dream girl for many.

One day, she had a dream, and the setting was in a novel. In the novel, for the sake of alleviating his pain of losing his wife, and soon his daughter as well, her father adopted a girl named Chen Xiangxiang who looked just like her. The girl was docile as a deer and very therapeutic, which made her all the more lovable. This girl became her substitute, and after a series of heart-wrenching incidents, everyone, from her father, brother, fiance, to her friends, they all doted on this girl. Meanwhile, she, the real rich daughter, was schemed against. After being disfigured, she jumped from a building and fell to her death.

Now, she returned to the moment when she was just discharged and before the tragedies happened. She lowered her head and looked at the person before her. She smirked. This time, she would control every development, and those who intended to harm her could forget about escaping.