In Mary Shelley's Frankenstein, the element of secrecy functions as a core and a central theme of the book through the story of Victor Frankenstein, portraying the danger of isolation and unchecked power, while highlighting human cowardice and and societal pressure, ultimately revealing the brutal effects of secrets on human life and relationships.

In the story told by Victor Frankenstein to Captain Walton, Frankenstein portrayed the initial consequences of secrecy on himself and people around him, highlighting the first dangerous aspect of it. Frankenstein was born into a prestige family, from whom he received unconditional love and happiness. But as he grew up, he abandoned everything, and kept a secret to himself about devoting his body and spirit to the pursuit of knowledge and the creation of an ideal being. Because to Frankenstein, "the world was a secret which [he] desired to divine." His decision to keep it a secret from anyone, even those that were dearest to him, signifies the character's shift from a life full of love to that in isolation, in order for his futile pursuit of forbidden knowledge to be successful. By strengthening his relationship with his knowledge and himself through a secret, Frankenstein detached himself from all other relationships, and even from nature; that secret took away from his life the people that were supposed to check on his actions and well-beings, making sure he lived a life he was destined to live. This secret of creating an unorthodox being also emphasized the broken relationship between him and God; the moment Frankenstein declared himself as a "Great God," he had rejected his role in the divine relationship where he was to act as a creature and not a creator, and this marks the start of all the horrible consequences that followed. Had Frankenstein ever told anyone about his secret desire, he might have been stopped by the people that actually loved him, before he went too high and fell too painful.

Later in Frankenstein's story, he revealed another secret that marks the collapse of his moral value. Frankenstein was heart-broken and immediately went back to his home in Geneva when he learned that his brother William was murdered and Justine, a pure and innocent girl, was being brought to court. Frankenstein's instinct told him that it was his own creature that caused the murder, but the moment Frankenstein had a chance to speak up, he kept it a secret. Frankenstein did not want people to think of him as a "mad man" who was talking nonsense about such a ridiculous being. Such inaction illustrates another fatal flaw from Frankenstein that stems itself from the secrecy of his work; Frankenstein's decision to keep it a secret, refusing to speak up the truth, resembles Frankenstein's cowardice that took away two innocent lives. By keeping the existence of his monstrous being a secret, Frankenstein was lying to himself and to the ones he loved, portraying his merciless abandonment of genuine, long-lasting human relationships in place of an unrealisitic and tragic relationship with his own knowledge, his own reputation, and his own creation whom he also abandoned.

Secrecy comes with consequences, and Frankenstein wanted Captain Walton to learn that. Towards the end of Frankenstein's story, it is revealed that the secrecy of his works took away everything from Frankenstein's life, especially the ones he loved the most. The moment Frankenstein destroyed the female creature, and the "Devil" threatened him that "[he] shall be with [Frankenstein] on [his] wedding night," Frankenstein, once again, kept his work a secret by dropping the female creature's parts down the ocean, and never revealed with anyone about the threat, or before that, the promise. Frankenstein promised his creation his companion in secret, and yet he decided to abandon that idea. After everything he had gone through, he still couldn't learn the lesson that the consequences of his silent secret are loud; his "secret" wanted him to hear it, to feel it deeply, by taking away the lives of his best friend Clerval, and the love of his life Elizabeth, which also led to the death of his own father. The brutal deaths of the innocent ones mark the ending of the secret about pursuing the forbidden knowledge: Frankenstein lost everything. Frankenstein started his secret by isolating himself and his work from everyone, but his secret revealed his flaws: irresponsibilty, futile ambition, cowardice, and how he was limitless, powerless, and could never be the Great God he desired to be. Frankenstein's secret promised him reputation and divinity, but in reality, it slowly destroyed his relationship with nature, with the people he loved, with his ambition, and with himself.