Hellboy, Vol. 5: Conqueror Worm
By Mike Mignola

Austria, 1939, is site to an experiment with the nazis and Oeming, the castle tower exploding. 61 years after this at BPRD HQ, a debriefing of what occurred back then is given, and when BPRD had investigated being the same night the place blew. Meanwhile, a nonthreatening comet heads for earth, and turns up being a nazi helmet. Laura is intro'd as HB's guide to get to the castle safely where it is calculated the helmet would crash.
Roger the homunculus has adjusted into current society fairly smoothly, but it hasn't stopped BPRD from fitting Roger with a kill switch bomb in case he becomes compromised, the agent giving HB liberty over the switch which he isn't please about. When they start their hike, Laura shares her 2st time going to the castle as a child, they being met by a dark-cloaked man warning of ghosts plaguing those who came there and to leave. When HB sees he's wearing a belt buckle with swastika, he clocks him, and Laura has Roger walk him away, she shooting the man, HB not aware, and she leading them closer to the castle. When she insists on going closer after HB instructs her to wait though, he becoming suspicious, esp after she claims to have read his file.
They are shot at, and HB attempts to help Roger from falling off the ledge they were on, but he falls down after telling him to help Laura, who had screamed. HB charges in and disables the rifle on auto. A skeleton warns him from the trap he was walking into, but it doesn't detour him, and HB is knocked out by a gorilla as Laura is praised by her grandpa, Von Klempt. HB is electrocuted awake and greets von Klempt, he going off to chat with Laura about how he'd gotten some of her men to collect Roger.
He just met a man who outs Laura for who she really was, before Roger goes back up to help HB. Roger's led to a secret way back to the castle, since most of the mtn is actually hollow, and being used to house experiments. The old machines begin draining Roger's power, but he wins out, draining the generator, through no fault of his own, which allows HB the chance to overpower the gorilla. HB's met by a ghost who wishes to help him after having let him live when he'd 1st came into the world.
The ghost provides the 1 thing to kill the invisible monsters living out in space. After the ghost moves on, Roger meets with HB and the 2 go in search of their enemies, as they greet doc Oeming joining them. Laura doesn't realize the havoc she'd help create, til after putting her gas mask on per von Klempt's insistence, HB coming in and seeing everyone collapsing. She runs off as HB fights von Klempt, and when he gets thrown through the floor, he wanders around and discovers a generator, and plug in with heads lined downward in a row on the machine.
Meanwhile, Klempt confesses to Laura of the true nature of the Conqueror worm, and how it'd consume humanity and everything. Oeming's body always having been meant to be used for the monsters in space to destroy humans. After this, the 1 who is 7 will help drain the Earth, and it will truly mark the end. As for Laura, he'd not meant to give her the impression she'd survive, but only wished to explain so she could better know why she would change, and die. HB sees Roger fall through the floor to his level and is updated about the worm killing the changed people.
When HB sees the worm for himself and is readying to use the lit up object the ghost had given him, Klempt's detached bod catches it, and crushes it. HB soon deduces the large worm doesn't like getting electrocuted, which is why Roger survived. HB comes up with a decent plan which he regrets, since it put Roger at risk, but Roger liked it, and reminds HB he isn't human, so doesn't death to him wasn't what HB thought. When Roger takes in the worm he struggles to return to himself, having enough time to get HB to use his fail safe bomb trigger.
Von Klempt tells HB he'd failed but Roger kills Klempt before falling outside into the snow. HB's able to save him, and then quite BPRD to go to Africa, he not having returned in a long while, and wished to start over, so says goodbye to Kate, who agrees to handle things back at HQ. Rasputin and Hecate chat about how he keeps failing to kill HB, but is optimistic he'd succeed. Instead, Baba Yaga considers him done failing, and puts him in a nutshell to wear about her neck. Great dang series! I'll miss the running story when I finish!