One scenario is when Harry is in danger during a duel or a battle. Snape might step in to shield Harry from a dark spell. Another could be when Harry is being bullied by other students or facing unfair treatment from the faculty. Snape, in these fanfictions, uses his position to protect Harry. For example, he might give Harry private lessons to improve his skills and keep him out of harm's way.
A possible scenario is that Harry is poisoned by a dark potion. Snape, being a Potions master, detects the symptoms early. He then spends days and nights trying to find an antidote and finally manages to save Harry. This long and intense process could make them realize their feelings for each other. Or, Harry could be kidnapped by a group of rogue wizards who want to use his power. Snape tracks them down and battles them to rescue Harry. After the rescue, the shared trauma and Snape's heroism could lead to a romantic relationship developing between them.
One scenario could be when Harry is facing a difficult exam. Snape, despite his usual gruffness, takes Harry aside and tells him to focus on what he's learned rather than stressing about the outcome. This simple yet firm advice calms Harry's pre - exam jitters.
Perhaps they are both transported to an alternate dimension where they have no prior grudges. They have to work together to find a way back home. In this new situation, they learn about each other's strengths and weaknesses without the baggage of their past in Hogwarts, which leads to them getting along.
One common scenario is after a battle. Harry is injured, and Snape, despite their differences, steps in to heal him. Maybe it's a fight against the Death Eaters where Harry is seriously wounded, and Snape realizes he has to put aside their enmity for the greater good.
One common theme is redemption. Snape, who has had a rather dark past in the original series, through rescuing Harry, finds a path to redemption and love. Another theme is the breaking of barriers. They come from different generations and have had a somewhat antagonistic relationship in the books, but in the fanfiction, the rescue event allows them to break those barriers and form a romantic bond.
In a gay romance fanfiction where Snape rescues Harry, the rescue could be both physically and emotionally. Physically, Snape might save Harry from a dangerous spell or a life - threatening situation. Emotionally, it could be Snape rescuing Harry from feelings of isolation or self - doubt. This could lead to a beautiful relationship where they support and love each other, perhaps defying the norms of the wizarding world.
Another scenario might involve an old, forgotten love potion in the Hogwarts castle that Hermione stumbles upon during one of her research expeditions in the restricted section of the library. The potion activates when she touches it, and she starts having dreams about a mysterious figure. She becomes determined to find out who this figure is while also trying to keep her condition a secret from her friends. As she delves deeper into the mystery, she discovers a long - lost love story that has some connection to her own family history.
One possible scenario could be in a potions class. Snape might be unfairly criticizing Harry's work as usual, but this time Harry decides he's had enough. He stands up, looks Snape in the eye, and calmly but firmly defends his potion - making process, explaining how he followed the instructions correctly. This could shock Snape into silence for a moment.
One interesting scenario could be when Harry uses a clever spell in a new and unexpected way during their exchanges, catching Snape off guard. For example, he might use a transfiguration spell to transform something in the classroom into a distraction while he makes a quick escape from Snape's scolding.