the_debt_of_time

Portkeys that are connected like your chain." She gestured to Sirius, who still wore his silver
chain Portkey, never having removed it once since she'd gifted it to him years earlier,
especially since it had saved his life. "Only, instead of keying them to a place, they would
be connected to another charmed item, a twin."
"What for?" Remus asked, passing the book back to Sirius, who took it
begrudgingly.
Mia threw her head back dramatically and sighed. "Honestly? I'm bored."
She had gone through Hogwarts twice now. While she fully planned on finally
completing her seventh year the following fall, there was only so much that she could do
without accidentally making herself Head Girl, a position she knew was meant for Lily. Mia
spent years holding back her own talent in class, doing what she could not to show off,
since she had not only already learnt most spells but mastered them years earlier, non-
verbally at that, and many even wandlessly. She spent a short time fourth year doing her
Animagus training, but aside from creating new spells, potions, and charms, Mia put all of
her effort into reinforcing her Occlumency shields and trying to learn Legilimency without
actually breaking into someone's mind against their will, something she found to be
absolutely foul.
Remus smiled at her affectionately. "I meant, what would you use these connected
Portkeys for?"
"Maybe for Aurors?" Mia suggested with a shrug of her shoulders. "Think about it.
Say an Auror is tracking someone who Disapparates. He can't be followed, especially if he
Apparated into a place where wards prohibit unknown entry, but Portkeys are different,
and they can override some wards. If the Auror were to slip a charmed half of a Portkey
into their target's robe pocket, they could follow them."
Remus raised a brow. "And appear out of the pocket."
"It's a work in progress." Mia scrunched up her face in irritation.
"It's genius." Sirius grinned. "I can already think of seven—no, eight—ways to use
them for pranks."