WARNING: The following contains spoilers for Locke & Key Season 2, now streaming on Netflix.

Locke & Key Season 2 continues the Locke family saga by introducing new threats and revisiting loose ends from Season 1. One of the loose ends concerns the altered memories of Duncan Locke, the only adult who wasn't affected by the "18 and up" rule, which is also known as the Riffel Rule in the comics.

As revealed in Locke & Key Season 1, Duncan had his memories altered after witnessing his older brother Rendell bludgeon his friend Lucas (who was possessed by Dodge) to death. This was accomplished by removing the memories with the head key and placing them inside jars. The memories were later buried in the Locke family cemetery and kept safe with the plant key. Without any clear explanations given, it was assumed Rendel and his friends chose to alter Duncan's memories as a way of removing a traumatic event from his life and preserving his better memories of his brother.

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In Season 2, the consequences of that decision are explored further, which makes Duncan a more tragic figure than previously established. After Rendell's former girlfriend Erin Voss makes a full recovery, she temporarily stays at Keyhouse at the insistence of the Locke family. During Erin's stay, Duncan is confronted with very vague memories of his past but is not able to fill in those blanks. This causes Duncan to experience intense mood swings around his brother's family and he gets especially angry in Erin's presence. These mood swings also coincide with him experiencing intense headaches, causing him to rest for long periods of time. He also socially withdraws by working on his car.

As Locke & Key Season 2 progresses, another reason is unearthed for why Duncan's memories had to be erased. It turns out Rendell and his friends discovered a way to remember the magical keys past the age of 17, which entailed making a memory key. However, the only Locke who could craft the key at the time was Duncan, most likely because he was the youngest Locke. As Season 1 previously established, only children and -- to an extent -- teenagers could locate and use the magical keys. Since Rendell was already close to 18 years of age and had just recently murdered his friend Lucas, he most likely couldn't make the key with a clear mind. This was where Duncan came in.

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Since making a magical key requires whispering iron, a blood sacrifice and the intent of a Locke, Duncan as a child was able to craft the memory key most likely due to his innocence. In the present timeline, the adult Duncan not remembering how to make new keys provides a temporary safety measure until Dodge starts looking for the memory key. This forces the Lockes to locate the memory key themselves to keep it safe from Dodge so the latter can't exploit Duncan's ability to make new keys. The memory key, however, isn't what's needed to restore Duncan's memories. Instead, the head key is used to place the memories back and fully restore Duncan's childhood history.

While Dodge still manages to get his way and succeeds at coercing Duncan into making a demonic key he can use to convert more people, he doesn't count on Duncan having the ability to control the very keys he makes. This proves useful in a fight against Dodge's demon army, as he can override Dodge's commands. Duncan also guides his nephew Tyler into crafting an alpha key that can reverse the changes caused by Dodge's demonic key.

Locke & Key Season 2 is streaming now on Netflix.

KEEP READING: Every New Key in Locke & Key Season 2 - and What They Do