Last week, following the first day of shooting on season four of Agents of S.H.I.E.L.D., the cast made their way to San Diego Comic Con, where they revealed the huge news that Ghost Rider would be joining the upcoming season. Unfortunately, because the cast had literally only been filming season four for a day, they didn’t have much else on deck to surprise fans with. (Not to say the Ghost Rider reveal wasn’t huge in itself.) Of course, jut because the cast isn’t too far into shooting the upcoming season it doesn’t mean that can’t talk about what to expect.

As the cast made their way through the press line at SDCC, was able to briefly speak with actor Iain De Caestecker, who has played the role of Leo Fitz since the show’s premiere. And naturally, the conversation seemed to immediately turn towards the status of FitzSimmons. Fans that watched last season will note that, after two season finales of torture and splitting the characters apart in one way or another, Fitz and Simmons (Elizabeth Henstridge) finally seemed to end the season on a happy note. Which would be promising, except, this is S.H.I.E.L.D. we’re talking about, and happiness only lasts so long. So it isn’t entirely surprising that, when asked about the two characters and what’s to come, De Caestecker made sure to state he expects something to go wrong.

“I think with any storyline, happy moments are inevitably, usually going to be followed by tragic moments, so I just see it, somewhere down the road, something has to go wrong,” the actor warned during an interview at the convention. “But for now they seem to be pretty happy! They got through that big bump of being able to be honest with each other, and tell each other how they feel about each other, which was a big deal for them. I think since they started at friends and were so close before they became romantic, that’s quite a good foundation for a relationship, right?”

Of course, as the show moves into its fourth season, one can only hope that they don’t try to destroy FitzSimmons solely for the sake of adding more drama*. After all, they’ve got a rogue Daisy “Quake” Johnson and a Ghost Rider to focus on these days.

The fourth season of Agents of S.H.I.E.L.D. will debut on ABC on September 20th at 10 PM EST.

*Note: As much as I enjoy S.H.I.E.L.D., there’s only so many times they can tear these two apart for the sake of a storyline.