Jesper met Wylan when he was apprenticing at the Tannery. Later on Wylan brought Jesper stroopwafels. And it ended up with them spending the night together. When Jesper woke up Wylan was gone. It wasn't until Jesper got back from Ravka they met each other again. Wylan was surprised to see Jesper but it was clear that Jesper did not remember their night together. And it wasn't until they were in danger and Jesper was on top of him that he remembered Wylan. A while later Jesper asked him why he didn't tell him that they met each other before. Wylan just answered that Jesper didn't remember him and Jesper defended himself by saying it was dark and when he woke up Wylan was gone. They got interrupted before Wylan could answer him and they had to pretend to be repairmen to fix the broken piano. After Jesper fixed the piano using his Grisha powers, Wylan sat down to play a melody and Jesper just stood there awestruck by Wylan.

When they returned to the cemetery they were hiding at, Jesper told Wylan that it wasn't his fight to clear Jesper's and the others' names. And Wylan asked him if he was worried about him. Jesper told him that he saw Wylan's face when the Crow club blew up and that he had no idea what he was getting himself into. Wylan looked at Jesper and told him that he knew now and he wasn't going anywhere. The day of taking down Pekka Rollins, they were looking at costumes to hide their identities, Wylan found a mask that covered his face, which lead to Jesper saying he kinda liked Wylan's face. After their names had been cleared Jesper and Wylan went to Wylan's workshop and had a talk about their night together. Wylan said that he left that morning because he though Jesper was going to do that and it would be easier to cut his losses. Jesper told him that he might have left him, but that was before he got to know Wylan. And that he can't make any promises or predict what will happen between them, but he would like to find out. Wylan tried to hide his smile but when Jesper expressed that silences aren't his favorite thing, Wylan ran up to Jesper and kissed him. Jesper expressed it was even better than last time after the kiss and Wylan ended up leading Jesper to the bed while saying that maybe Jesper needed a fuller reminder.

Few days later, while in bed Jesper tells Wylan he quite likes how he looks in the morning which leads to them sharing a small kiss. After Jesper asked him if he was hungry and talked about a place they could go to, Wylan told him that he wasn't sure if he was ready for breakfast just yet and they ended up kissing some more but before it could lead to something more they got interrupted by Kaz saying Ravka needs saving. When they got their fake passports to go to Shu Han Jesper complained about him being older than last time to Wylan. Wylan answered that technically he is older than last time. Jesper gave him a look and then saw Wylan's fake name, stating that it was a terrible name. Wylan asked what is said and Jesper - without thinking - asked him if he couldn't read it. Seeing the look on Wylan's face Jesper tried to smooth things over by saying he can barely read it himself but the damage was already done. Wylan started to avoid Jesper.

Jesper tried to talk to Wylan while they are in the market in Shu Han. He tried to talk about Wylan's love for chemistry and at first it seemed to work because Wylan answered his questions. But when Jesper said that Wylan must be the smartest person he knows, Wylan walked away from him again. It wasn't until they were at Ohval Saran that Jesper tried to apologize to Wylan, saying he honestly didn't know that Wylan couldn't read because how could he when Wylan is so clever and smart. Wylan asked Jesper to just stop to patronizing him and that he hates it. Jesper just wanted Wylan to know that he has nothing to be ashamed of. But Wylan pointed out to Jesper that him trying to tell Wylan how to feel about his shame isn't fair, when Jesper is hiding the very thing that makes him special. Jesper tried to joke about his face but Wylan interrupted him saying he knows that Jesper is
a Grisha. Wylan explained that he has seen him shoot all those impossible shots and that piano wire didn't just fix itself. Wylan said he doesn't understand why Jesper keeps it a secret because Jesper is a Zemeni and Zemeni believe that Grisha powers are a blessing. Jesper, with tears in his eyes, tells Wylan that it is not a blessing but a curse and that Wylan has no idea what it has cost him. And Jesper walked away from Wylan.

After Wylan saved Jesper and the others from the poison that was slowly killing them and they got the sword they came for, Jesper told Wylan that he was right and that Jesper doesn't want to hide who he is anymore. He stated it's for a millions reasons and that includes Wylan. Wylan smiled and told him that he saw a Datura Meloxia and they are extremely rare and that when he saw it all he wanted in the world was just to tell Jesper about it and squeeze his hand. Jesper took Wylans hand and said that he wants to stand with him in front of all the Daturma Ox things to come. Wylan at first tried to correct him but changed his mind and just kissed Jesper.

Back in Ravka they helped out against the Darkling's followers. When they won the battle. They tried to find Alina and the others. But they got trapped in a room with one of the shadow monsters. Wylan told everyone to shield their eyes and he threw a bottle at it which made it vanish for a few minutes. Jesper screamed out that Wylan is his man and then remembered that they haven't actually put a label on it yet. Later on Wylan is on the floor with Jesper checking on him. And when Darkling died, the shadow monsters went away too and they were able to leave the room. Jesper was close by Wylan to making sure he was alright.