


The fact that the killings started up again made L feel like something drastic had to be done, so he planned to have death row inmates experiment with the notebook so they could verify if that 13 day rule was real. Rem had also helped make that rule seem real, as she lied about it being genuine, but it was already being suspected by L as a fake nonetheless. The Death Note that they got from Higuchi was the one that had the fake rules written in it (one being that if you don’t continue to write names in the DN for 13 days straight after using it, you will die), which Light added to help himself and Misa seem more innocent due to their captivity, and is the main reason L releases Light from the handcuffs and lets Misa go free. I imagine Light and L would end up just focusing on getting more information from Higuchi, as well as figuring out exactly how the Death Note worked so they could deduce who the original Kiras actually were. If Light still had not regained his memories at this point he would still be trying his best to help L solve the case instead of working against him, and he would not be giving any orders to Misa at all. Misa digging up the other Death Note, making the second eye deal to halve her lifespan, and once again starting to kill criminals were all Light’s sneaky way of making her seem in danger and suspicious again and putting lots of pressure on Rem and L to act. If Light’s memories never returned he would never have told Misa where to find the other Death Note once she was released from captivity, so even if she still had her own Kira memories she wouldn’t have been able to find the other notebook nor start the Kira killings again. She may not have been released by L at all if Higuchi had managed to be questioned by L, but I can’t say for sure. L had to release Misa after they got Higuchi because he didn’t have the evidence to keep her confined any longer in the manga, which meant she was able to go dig up the other Death Note again.

I can’t think of any specific stuff right now, but this would’ve probably given L that much more insight into the ways which Light and Misa might’ve been duping him all along. He had already demonstrated that he was very willing to cooperate and tell them about the notebook and its powers right before he died, so I’m sure Higuchi would’ve told them useful new stuff about how Kira’s powers and the Death Note actually worked. If Higuchi had been successfully taken into captivity they would’ve questioned him about everything he knew. If Light never touched the notebook after it was retrieved then Higuchi would’ve been successfully taken into captivity. That’s a very good question and also probably a really complicated one to try to figure out completely realistically! But let’s just say L never let Light touch the notebook in the helicopter and then try to figure it out from there.
