The Presidents of the US and China will meet in the coming hours to try and repair their relationship.
It's one of the most consequential in geopolitics and tensions have been simmering for months.
Arriving in San Francisco, US President Joe Biden touched down for a showdown with his Chinese counterpart.
But after months of frosty relations with Beijing, Washington is looking to thaw the ice.
On Wednesday, Biden laid out what he hopes to gain from a meeting with China President Xi Jinping.
"To get back on a normal course of corresponding," Biden said. "Being able to pick up the phone and talk to one another if there is a crisis. Being able to make sure our militaries still have contact with one another."
Right now, they don't have contact because China cut off military communications last year.
Biden's meeting with Xi comes during a turbulent time in geopolitics, with wars raging in both Ukraine and in Gaza.
But the US is also concerned by rising tensions in the South China Sea and Beijing's territorial claim over Taiwan.
Relations plummeted further when the US shot a balloon out of the sky earlier this year it and claimed it was a Chinese spy balloon.
"This is a complex relationship, a competitive relationship, which could easily veer into conflict or confrontation if it's not well managed," US national security advisor Jake Sullivan said.
While Biden and Xi aren't expected to be singing kumbaya, there will be some diplomatic progress; like their militaries talking again as well as a deal to halt the flow of the drug fentanyl between the two countries.
In recent years, China has been the primary source of fentanyl trafficked into the US.
The meeting will be a chance to reboot one of the world's most important relationships during troubled times.