As a native English speaker, I don't see any difficulty with this sentence. It doesn't matter whether Karen intentionally disappeared, or whether something caused her to disappear.

The formulation "lead to" simply means "caused" in this context. So the plot revolves around what caused Karen to disappear. What we are interested in in the sentence is the set of circumstances that caused the disappearance --either by influencing Karen such that she decided to disappear, or by influencing some other agent to kidnap her or persuade her to elope or whatever it may be.

Once we have the context, we'd know how exactly the disappearance manifests, but it wouldn't tell us anything new about the verb phrase "lead to".

As a native English speaker, I don't see any difficulty with this sentence. It doesn't matter whether Karen intentionally disappeared, or whether something caused her to disappear.

The formulation "led to" simply means "caused" in this context. So the plot revolves around what caused Karen to disappear. What we are interested in in the sentence is the set of circumstances that caused the disappearance --either by influencing Karen such that she decided to disappear, or by influencing some other agent to kidnap her or persuade her to elope or whatever it may be.

Once we have the context, we'd know how exactly the disappearance manifests, but it wouldn't tell us anything new about the verb phrase "led to".