Disclaimer: Harry Potter and all its characters are owned by J. K. Rowling.
The next day, having set the planned traps and alarms, Lily sent a message to Remus updating him. She also owled a badge for signalling him in case of an attack on their home by Voldemort.
Her plan was to have Remus arrive invisibly some distance away from their house to avoid detection. If Pettigrew was present in any form, then once Voldemort entered the house, he was to find and stun Peter, side-along apparate him to his location, put a Body Bind Curse on him and bind him in ropes, take a snapshot of the Dark Mark on his arm, feed him Veritaserum and have him state all the details about his role as a spy and then await Lily's instructions.
One good thing about Veritaserum is that once in, the person being interrogated has no control over his body. This would mean that the rat would not be able to escape while under its influence.
Once the danger had passed, Lily would send her elf to Remus who would hand over his memory of the interrogation and the developed photo of the Dark Mark on Peter's arm.
Hopefully, if Voldemort was captured as planned, and then interrogated under Veritaserum himself, James would realize the truth about Peter. She would then let him know that she had suspected this all along and that Remus had been helping her, having convinced him first as James and Sirius were too blinded by their faith in Peter and their recent prejudice towards Remus because of him being a werewolf.
Having prepared a messaging set for communicating with Alice too, Lily was in constant touch with her and Alice was planning similar traps in case of an attack. It was quite possible that Voldemort might send his minions to capture Neville as they weren't under a Fidelius while he himself went after Harry.
Alice too had hired a house elf, Pintel, and instructed him to protect Neville in a similar way. The Longbottoms and Potters would be each others' backup.
Meanwhile, they also had another thing to worry about.
What to do if a Killing Curse was fired at one of them? It cannot be stopped by any shield charm, after all.
Once again, it was Lily who came through. As a Killing Curse can be shielded by a physical object, she designed a password-activated wristband with a transparent dial resembling a watch to be worn on the non-wand hand. The password would enlarge the dial into a large and inch-thick glass shield which was already spelled with an Unbreakable Charm and had a two-inch wide hole in the right side to push the wand through. It not only enabled the caster to shoot spells without lowering the glass shield but also see the attacker through the glass, thus acting like a mobile bastion of sorts like the permanent ones found in old forts for firing arrows or shooting bullets while offering passive protection.
As James being an Auror had permission to cast the Killing Curse in defense, and they were living under Fidelius, he was able to test the magical glass shield. The shield not only held but also rebounded the curse back. Thankfully, James had cast it from behind a partially open door and the shield was placed at an angle because of which the rebounded curse only ended up destroying a flower vase, nothing which a Reparo could not fix.
Lily made these shield bands for herself, James, Alice, Frank, and both of their elves. She dared not send one to Sirius for fear that Peter might come to know and pass on that intel to Voldemort but she did send one to Remus.
Lily later decided to put the wind chime traps in the other rooms too because Voldemort might as well blast his way in through a side wall, anticipating their frontal attack preparedness.
Alice copied all of Lily's ideas but not only placed the traps in the home they were hiding in but also at Longbottom Manor where her mother-in-law, Augusta Longbottom still lived.
The two couples also laid the sneakoscope alarms in their lawns at various spots and included them in their respective maps.
Now, all they had to do was wait.
As Harry's room was upstairs, James and Lily had begun to spend most of the time there, as sending Nyssa and Harry away on being alerted to the attackers' presence would otherwise be time-consuming if they had to go up the stairs first and then tell their house-elf. They wanted to be able to do it quietly without anyone being the wiser.
The wait during the following days was nerve-wracking as they didn't know whether it would be days, weeks, or years before they would be able to come out of hiding. Only Lily knew it was a matter of days before Peter would lead his Master to their place but still, the wait ate at her.
Then finally, one day, it happened.
One Halloween night, the Potters' sneakoscopes began pinging on the map. First, it was at only one place, indicating the front gate. After that, the point midway on the garden path where one of their sneakoscopes was buried, pinged while also showing another active point still at the gate.
As the distance between the two points was big enough, it was easy to deduce that there were two untrustworthy people, one of whom presumably Voldemort was silently walking down the path inside, to their house while the other remained stationed at the gate itself.
The map's intentionally soft pinging had been made to resemble an insect sound due to which it was ignored by those outside the house but it instantly started a flurry of activity within the household.
First off, Lily signaled Remus abt the attack with a tap of her badge and then sent Nyssa and Harry down the disillusioned chute after casting a Sleeping charm on Harry. While Lily was doing that and observing Nyssa sliding down the chute with Harry strapped to her in a baby carrier, James stood at the door, watching the map, his wand held in preparation with his glass shield expanded.
The chute went right up to the backyard fence, which had a small gate. At Nyssa's touch, the gate opened silently, and once she stepped out, she apparated away to Alice's place with barely a pop that went unheard in the sounds of insects.
It barely took a minute as Lily had not waited to check movements on the map after the first ping as James was keeping an eye. Seeing them safely gone, Lily joined James, extending her own glass shield and then they both rushed to the top of the stairs but didn't go down. They had decided that if they were at the top of the stairs at the time of any attack, then they would not give up the height advantage over the enemy and had also magically reinforced the area to repel any explosive curse.
Just as they reached the top of the stairs, Voldemort blasted the front door off its hinges. As soon as he walked in as if he owned the place, he heard Lily say, "Welcome, Dead Boy."
The following moments would forever be etched in their memories.
One moment, Voldemort was about to say something insulting to the pair, and the next moment, a cauldronful of the pranking potion got dumped on his head which had him spluttering. He got over his shock quickly and began silent spellcasting, unable to say the incantations aloud but James was prepared and immediately started on his own spell chain.
One of the curses Voldemort had fired was the Killing Curse but just as tested, it hit Lily's shield and rebounded back to him. Voldemort dived to avoid it but then his form began to change, courtesy of the potion, turning black and white while he shrank.
What James saw there then, had him almost fall down the stairs, laughing.
Voldemort had been turned into a penguin and was struggling to get out of his now very large robes!
Unable to hold the wand in his transfigured arm, it had fallen and clattered to the floor.
While James was laughing his head off, Lily, the calmer of the two, summoned Voldemort's wand, cast a sleeping charm, body bind curse, and Incarcerous spell on Voldemort (whom she had now mentally dubbed the Penguin Lord) thus making it impossible for him to move.
Meanwhile, Remus had finished his own task outside. He had crept behind Peter who was not even in his rat form, stunned him, and taken him away.
The danger had passed. The Dark Lord or rather the Penguin Lord and the rat were their captives now.
And there it is, guys! My new chapter. Hope you like it. See you with the next one soon.