SKYNET?

lol timeskip. Recent explosions and mysterious occurrences. Cue to protagonists, Mimi brings Rin water Vodka as usual, and Maeno is… OLD. O_O They receive a call, which leads Rin to the roof of some building in construction. There, she meets some loony girl in a bloody meidu outfit, who utters some nonsense before falling to her death. Meanwhile, all over city, seemingly random bombings take place.

Rin's investigation leads her to find some information on a place called Death's Island, where a disease named Higan was rampant. Death's Island used to be a testing ground for biological weapons, but was later eliminated. (How do you eliminate an island?) This was back in World War II, so most people who know about Death's Island are now elderly citizens. Nevertheless, it becomes clear that the random bombings are actually targetting these elderly citizens. (Oh smart. Not like that's a big giveaway to what the bad guys are up to.)

maji-desu? How do you blown up an island with a landmine?

A certain symbol reoccurs during the episode, sometimes with or without the characters' knowledge.

Meanwhile, Maeno spends time with his family (family?!), he apparently married Yuki from Episode 2 (and had a kid!). Elsewhere, Rin is attacked - more specifically, she is shot dead. Except Rin wouldn't die even if she was killed. Waking up, Rin finds herself in a strange facility, and upon further exploration finds none other than that psychotic piercing lady Sayara alive.

Mimi and Maeno's search for Rin leads to dead ends, so they are forced to ask the lesbian information lady for help. After lol lesbo secks, the lady identifies the symbol as Kudoru, short for Kudorusyochisu, which means evil in Sanskrit.

Rin, now a captive of Sayara, is experimented on for the latter's wanton desires. Sayara is alive because she's taken a time spore, and says that one's body says forever in the condition it was in when the spore was taken. She refers to the mysterious tree as 'Yggdrasil'. Blah, blah Rin manages to escape the facility, only to find herself on none other than Death Island. Sayara chases Rin around in a powered body suit, spilling the contents of her evil plan - she intends to spread the Higan virus around the world, eliminating all those who are not immortal.

Maeno finds Rin tied to the railing of Kudoru's container ship, and proceeds to save her. In doing so, he gets shot by Sayara in the back. He tells Rin to go stop Sayara, and then uses his secret weapon - Yuki's brother's time spore. Sayara has Rin in a death grip again when Angel-fied Maeno rushes in to save her, and flies her away from the ship. When he reaches his limit, he drops her into the ocean, then heads back to feed on Sayara. Apos makes a timely appearance, taking out Maeno's time spore (effectively killing him), but loses that, so he takes Sayara's and eats it.

In the aftermath, Maeno's death is taken hard by Rin, Mimi, and Yuki.

Thoughts:
As usual, I had no idea what was going on during the episode. Rin and Maeno went around finding clues, but how they even knew what clues to look for was beyond me. Maybe I'm dumb. Anyway, ignoring Sayara's oh-so-typical-I'm-going-to-kill-all-humans plan, there are some things that were made clearer in this episode.
 - Apos seems to be some sort of time spore keeper, but he's pretty antagonistic. The reason behind his demented treatment of immortals (stabbing them with various swords, etc.) is revealed when he says that painful, hurtful, and hateful memories taste best. Since he eats Sayara's spore at the end, it can be concluded that time spores carry the memories of those who used it. Additionally, Apos appears to be 'farming' Rin, as he said he can't wait to eat her, when it seems like he could take her spore whenever he wants to.
 - When one becomes an immortal, that is, when someone takes a time spore, her body is forever stuck in the condition when she took the spore. Sayara, who had been assaulted by zombies, was able to survive thanks to the spore, but she was likely crippled, hence the need for the powered body suit. This is also supported by Rin's constant need for glasses.
 - The 'spore' tree is referred to as Yggdrasil, or world tree. Where and what it is, though, seems unknown.
 
Rather sad that Maeno only lasted 3 episodes, half of the entire Mnemosyne OVA. Wonder how it'll proceed from here?