soulmate au where each pair of soulmates is gifted a identical plushie each after they're born. people everywhere carry around their plushie so try and find their soulmate.
some people who have never found their soulmate/ lost their soulmate in an accident will display the pairs of plushies on bridges or put them on their dashboards.
situation A: Person A lost their plushie when they were young and sets out on a mission to find it along with Person B, who is unknowingly their soulmate
situation B: Person A finds an identical plushie to theirs tied to a bridge railing, meaning that their soulmate has given up looking for them.