A bridge designed for vehicles rather than humans.
A bag.
A beach with an abundance of flat stones. Pebble beaches in France are a nice option.

Of note, you will need to be in the beach during the day and travel to the beach by night, so ensure they are close. I would recommend the Île de Ré bridge, to go with the previous suggestion.

On the beach, collect nine hundred ninety nine flat pebbles. Not one more, not one less. Put them in the bag one by one, and count them as you do so. Remember which number belongs to each stone, but keep in mind you cannot mark them in any way.

Shake the bag before you leave the beach, and thanks the sea for providing you with it’s blood. Travel to the bridge, and ensure you arrive on the same day. Walk on the outside of the left side the bridge, as close to the edge as possible, until you reach the center of it. Start skipping the stones in the same order you picked them up. Each stone should skip no less than three times, and no more than five. If at any point you make a mistake, someone from the Wrong Turn will rise from the water, their shape all twisted and bent, their limbs extended into monstrous tentacles while still feeling like fingers, and their faces misshapen into something out of a deep diver nightmares. They will grab your ankle and pull you into the water. If you survive the fall and manage not to drown or die of hypothermia, avoid bridges in the future, as they will keep trying to kill you until they succeed.

If you did everything correctly, you will hear some giggles from your right. Turn towards them and you will see a Pearl from the Dreamscape. She will have short white hair, a mature face with a beautiful smile and teeth as white as the moon. Her skin will be pale, almost milky, and despite her being older than you, it will be soft and smooth as silk. She will laugh when you see her, clearly delighted by your actions. Move closer to her, and she will hug you, pushing you towards her bosom, in a warm, motherly embrace. Stay there, and let the sound of her heart heal you. You will cry, remembering how much your actions hurt those around you, but she will forgive you. As your sins wash away, melting into her, she will keep tightening her embrace, until you lose your ability to breathe. Fear not. Let her suffocate you. You will pass out.

When you wake up, you will be in a cabin, lost in the woods. A man with broad shoulders will be standing next to a chimney, with a roaring fire that will bring warmth to the room. Say hi, and you will become engaged in a conversation about this man and her wife. She was the one who you met on the bridge, and through his words, you will get to know her. She is a caring, nurturing soul, that has always brought joy to those around. The man loves her with all the strength of a heart that has being toughened by the wars, and his sole regret is that he will never be able to give her a child.

The woman will walk in with dinner for the three of you, and a bottle of wine. You will eat, and share a wonderful time with two incredible souls, wise beyond their appearance and culture.

At one point during the night, the man, emboldened by wine, will suggest it. The woman will hesitate, and you will be too shocked to speak. There will be some awkward silences, until the man insists. More wine will be served. You will laugh and share. It is not, you will notice, an idea that any of you dislikes. It’s just unusual.

You will sit on the edge of the bed, while the man grabs a seat and sits in the corner of the room. She will come in, looking stunning in a white gown that falls onto the floor, and reveals every shape and detail of her body; her pink nipples, her bellybutton, her freckled shoulders. She will look tentatively at her husband, who will smile warmly, with a love so deep that it transcends the physical idea of possession and jealousy. She will then walk over to you, confident and passionate.

"I’ll take the lead, if you don’t mind,” she will say. You will nod, and let her remove your shirt. She will run her hands through your hair, tussling it and making a mess. She will give quick glances over to her husband, who is always watching, always smiling, proud and loving. She will then kneel in front of the bed, and will pull your pants down. Your dick will be already hard, and she will take it with strong, experienced hands, and smile at you while she begins to gently move her hands. She will lean forward, and opening her gown, will let your cock slide between her milky white, warm breasts. Relax, and let the feeling of being watched become just a minor concern in your mind. She will use her tits to masturbate you, spitting from time to time to ensure your dick keeps wet. Once she considers you are excited enough, she will let go of you, and stand up. She will turn around and bend over slightly, so you will get a very nice view of her ass as she sits on your dick, letting it move inside her with ease.

You will grab her waist, but you don’t have to. She moves just like she lives, spreading warmth and love to those around her. Every time she raises her ass, your body will try to follow, but she will always push back down again. You will feel the warmth of her pussy bringing you closer and closer to the edge. Her back, pale and freckled, will hold your attention as you keep pushing deeper into her. You probably won’t notice as her husband moves closer, massive dick in hand, and she greedily takes him into her mouth. You will just feel the tender wetness that surrounds you, and the bouncing of her ass on your dick. As she pleasures both of you, you will notice her back stiffening, and her voice becoming deeper, her moans becoming muffled cries of pleasure.

You will notice her orgasm as she tightens up around you, and will let yourself go, filling her with all that you have. You will collapse onto the bed, your hands still on her hips, and will stay inside her for a few moments, as you grab your bearings again. She will stand up, and hug and kiss her husband, who has a smile that fills you with love. You will fall asleep while realising that nobody kissed or hugged you.

Some time after you wake up, you will receive a postcard with no return address or stamp, with a photo of the couple with a newborn baby that looks nothing at all like you. You will never again be able to take more than nine hundred ninety nine steps on any bridge.

Addendum A-00738-A

Dear Dr. [REDACTED]:

I’ve been considering this ritual in relation to our latest talk. We mentioned how strange it was that the Seekers were able to find all these intricate steps and follow them without dying to any mistakes or creatures from the Wrong Turn. Your theory that they craft the rituals themselves still feels counterintuitive to me, and I much prefer Dr. Mabuse theory that states that they find them from previous Seekers. There is much that we do not know, and we only have the journals of six Seekers, but we don’t know how many they are, or how many have already died.
However, here’s a different idea.
I’ve been obsessed with 00738 for a while now. These, of the Rituals we have studied, seems the most like a trap. I think it’s possible that some Seekers are actively trying to sabotage the Institute and are feeding us misinformation. The A. A. Aleister journal was suspiciously easy to find (please find the attached presentation), and many of the rituals in it are dangerous. I’m concerned at how hard this one tries to get us to go to France, when we know full well that we wouldn’t survive for a minute there. Perhaps some of these don’t work, and are designed to get us to try just to weaken us.
Sincerely,
Dr. Malcolm.

Addendum A-00738-B

From: Dr. [REDACTED]

For: Dr. Malcolm.
Request: One (1) round-way ticket to France.
Comment: Despite France being on the No-Travel list after the [REDACTED] incident, I feel that the danger has already passed. Our latest scans have revealed no living entities in most of continental Europe, so we have deemed this to be a safe journey.

Addendum A-00738-C

As decided by Dr. Smith and Dr. Smith, due to the untimely death of Dr. Malcolm and her team, further travel to any country affected by [REDACTED] is now prohibited.

Addendum A-00738-D

Wait. If this went through the Smitherins… Why does it still say France???