Seattle (11-6) improved to 2-0 in the beginning stages of a WNBA-record nine-game homestand that won't see the Storm head on the road again until mid-July.
Clark finished with 15 points and seven assists, playing before another sold-out crowd with many fans wearing various No. 22 jerseys with her name across the back.
But it was Loyd who put on the show.
"We knew it was coming and when it comes, it comes in a storm. In a barrage. We know she can rattle off points," Seattle coach Noelle Quinn said.
Loyd made five 3-pointers in the first 20 minutes and her 23 first-half points were the second-most by any player in the WNBA this season. She also missed nearly five minutes of the half after getting inadvertently hit around the left eye late in the first quarter.
Loyd finished with six 3-pointers and made 10 of 15 shots overall. It was her second game this season with at least 30 points — both coming against Indiana. She has 23 career games of 30 or more points, tied with Tina Charles for sixth-most in league history.
Loyd had gone four straight games without reaching the 20-point mark, including a loss to Las Vegas where she missed all nine shots and finished with one point.
"I feel good. I felt good before. Sometimes they just don't go in," Loyd said.
For the second time in five weeks, Climate Pledge Arena was sold out for a visit from Clark and the Fever with more than 18,000 in attendance. This time the crowd included the likes of Sue Bird and Megan Rapinoe, Pro Football Hall of Fame inductee Walter Jones, J.P Crawford from the Seattle Mariners and the Milwaukee Bucks Damian Lillard.
Seattle made the night difficult for Indiana's star rookie, especially in the second half when Clark was often forced to give up the ball because of how the Storm defended the pick-and-roll. She attempted just two shots after halftime and finished the game shooting 4 for 9, including 3 of 7 from 3-point range.
There were also times that Clark was open and teammates weren't able to find her.
"When you're playing off a ball screen a lot and you get blitzed, you're just going to have to give the ball up. That's just kind of how it rolls," Clark said.
Clark appeared to tweak her left leg early in the first quarter on a drive to the basket, but she waved off the need for a substitute. It took her more than eight minutes to find the scoresheet on a deep 3-pointer. She finished with 12 points in the first half, but that wasn't enough to keep up with Loyd at the other end.
"We're competitors. We want to win. It didn't ever really feel great out there tonight even when we cut it to nine. It just didn't feel like it was flowing too well," Clark said.
Ezi Magbegor added 18 points and Nneka Ogwumike had 15 points and 11 rebounds for Seattle.
Erica Wheeler also scored 15 points for Indiana and Kelsey Mitchell finished with 14.