diff --git a/crates/benilla-ui/src/script/trainer/mod.rs b/crates/benilla-ui/src/script/trainer/mod.rs
index f8117bf1..56a127e7 100644
--- a/crates/benilla-ui/src/script/trainer/mod.rs
+++ b/crates/benilla-ui/src/script/trainer/mod.rs
@@ -466,8 +466,24 @@ pub(super) fn install(lua: &Lua) -> mlua::Result<()> {
                 Row::Service(si) => {
                     let s = &t.services[si];
                     Ok(MultiValue::from_vec(vec![
+                        // The name may be nil, and the stock window says so itself: it tests
+                        // `serviceName` before using it as a header's (`Blizzard_TrainerUI.lua:209`)
+                        // and falls back to `UNKNOWN` for a service's (l.287).
                         opt_str(lua, s.name.as_ref())?,
-                        opt_str(lua, s.subtext.as_ref())?,
+                        // The subtext may not. It is empty for a spell with no rank, never nil:
+                        // the client reads it from the spell record's string block, where an
+                        // absent rank is the empty string at offset 0 rather than a null.
+                        //
+                        // It has to be, because the stock window formats it **unguarded** —
+                        // `ClassTrainerSubSkillName:SetText(format(PARENS_TEMPLATE, serviceSubText))`
+                        // (l.275) — twenty lines before its own `not serviceSubText` fallback.
+                        // A nil raises there and takes `ClassTrainerFrame_Show` down with it,
+                        // after `ClassTrainer_SelectFirstLearnableSkill` and before
+                        // `ClassTrainerFrame_Update` (l.48-49), so the list never populates and
+                        // `SelectTrainerService` (l.277) never runs: a trainer window that shows
+                        // nothing and trains nothing. Every rank-less service reaches it — every
+                        // profession recipe, and class abilities like Parry.
+                        Value::String(lua.create_string(s.subtext.as_deref().unwrap_or_default())?),
                         Value::String(lua.create_string(s.category.era_str())?),
                         Value::Nil,
                     ]))
diff --git a/crates/benilla-ui/src/script/trainer/tests.rs b/crates/benilla-ui/src/script/trainer/tests.rs
index def3be58..2c0f71e6 100644
--- a/crates/benilla-ui/src/script/trainer/tests.rs
+++ b/crates/benilla-ui/src/script/trainer/tests.rs
@@ -660,3 +660,35 @@ fn talent_order_sorts_on_state_within_a_group() {
     let got: Vec<String> = visible(&mut s).into_iter().map(|(n, _)| n).collect();
     assert_eq!(got, ["Riding", "Aye", "Bee", "Cee"]);
 }
+
+/// A rank-less service's subtext is the empty string, never nil. `Blizzard_TrainerUI.lua:275`
+/// formats it unguarded, so a nil raises inside `ClassTrainer_SelectFirstLearnableSkill` and the
+/// `ClassTrainerFrame_Update` on the line below it never runs: an empty window that trains
+/// nothing. Every profession recipe and every rank-less ability (Parry) takes this path.
+#[test]
+fn a_rank_less_service_subtexts_empty_so_the_stock_window_can_format_it() {
+    let mut parry = svc(3127, "Parry", TrainerServiceCategory::Available, 26, "Arms");
+    parry.subtext = None;
+    let mut s = UiScript::new().unwrap();
+    s.set_trainer(Some(TrainerState {
+        greeting: "What would you like to learn?".into(),
+        trainer_type: 0,
+        groups: Vec::new(),
+        services: vec![parry],
+    }));
+    // Row 1 is the group header, row 2 the service.
+    assert_eq!(
+        s.eval::<Option<String>>("local _,sub = GetTrainerServiceInfo(2) return sub")
+            .unwrap()
+            .as_deref(),
+        Some(""),
+        "a service with no rank subtexts empty — nil is what broke the window"
+    );
+    // `ClassTrainerSubSkillName:SetText(format(PARENS_TEMPLATE, serviceSubText))`, as written.
+    assert_eq!(
+        s.eval::<String>("local _,sub = GetTrainerServiceInfo(2) return format('(%s)', sub)")
+            .unwrap(),
+        "()",
+        "the stock line must not raise"
+    );
+}