“A shield tithe works like that, except it guards you against curses instead of blades. And it lasts far longer than the impervious tithe—or any tithe. It lasts a whole day, one sun cycle.”

Akeylah whistled softly. “Why wouldn’t people use it all the time, if it’s so effective?”

Zofi traced the outline of the drawing. “Because it closes you off. Nobody can curse you, but you can’t tithe either, for as long as the shield lasts. You can’t heal yourself from a knife wound; you can’t tithe for speed or strength, nothing.”

Even boosts wouldn’t work. Mother had taken great care to warn Zofi about how dangerous it would be to try, back when Zofi was little. “Boosting with a shield tithe is like lighting a fire under your own feet,” she’d said. The tithe would have nowhere to go but into your veins.

“Doesn’t sound so bad to me,” Akeylah was saying. “Being shielded would be like being Genalese.”

Zofi scrunched her forehead. “Maybe. But like Genalese soldiers facing our Talons, it would leave you defenseless against any other kind of attack, by sword or cannon or—”

“You said it lasts an entire day?” Akeylah interrupted, clearly not wanting to dwell on the morbid possibilities.

Zofi nodded. “If you perform a shield tithe at sunup, it lasts until the following dawn. It’s nicknamed Father Sun’s Favorite.”

Akeylah met her gaze. “Do you think we should start using it?”

It would leave them vulnerable to normal attacks. But normal attacks weren’t their concern just now. All she could think about was what would’ve happened if Sarella hadn’t stumbled across Ren in the baths yesterday, or if Akeylah hadn’t known what to do with a drowning victim.

“I think so,” Zofi finally answered. Better to shield than die like Ren nearly did.

“Can you show me how?” Akeylah offered up her own bloodletter. “We can teach Ren when we visit her this afternoon.”

Zofi talked Akeylah through it first. Then she shielded herself. One shallow, paper-thin cut and the tithe flooded her veins. She saw her body in her mind’s eye, bright with the Arts. She caught all that brilliant potential and spread it out like a blanket. Wrapped it around her body as if to ward off a chill on a cold night. The moment it engulfed her, she lost the ability to feel the Arts.

It was like stuffing her fingers in her ears or pinching her nose. The world took on a duller shine, with a sense of something important missing. But that was reassuring. If she couldn’t sense the Arts, the heir couldn’t reach her either.

Not today, anyway.

That evening, Zofi skipped dinner and started walking back to her chambers early. A day of reading had left her eyelids drooping and her head afloat.