diff --git a/src/parser/mindmap.ts b/src/parser/mindmap.ts
index 57153bd..c5477a5 100644
--- a/src/parser/mindmap.ts
+++ b/src/parser/mindmap.ts
@@ -240,6 +240,8 @@ export const addTopic = (parentObject, mainTopic = "Main Topic", options = {}) =
     id: UUID(),
     title: mainTopic,
     titleUnedited: true,
+    boundaries: [],
+    summaries: [],
     ...options
   }
   parentObject.children.attached.push(topicObject)
@@ -331,6 +333,8 @@ export const addSingleSummary = (parentObject, topicObject, options = {}) => {
     id: UUID(),
     title: "Summary",
     titleUnedited: true,
+    boundaries: [],
+    summaries: [],
     ...options
   }
   parentObject.children.summary = parentObject.children.summary || []
diff --git a/src/parser/mindmark.ts b/src/parser/mindmark.ts
index 83990a6..4c310e5 100644
--- a/src/parser/mindmark.ts
+++ b/src/parser/mindmark.ts
@@ -43,6 +43,23 @@ function addLine(line: string, status: any) {
 
     status.lastTopic = topicObject
 
+    // Update levels array, setting summary topic as new parent topic level
+    // Use appropriate indentation level to ensure subsequent subtopics can correctly identify their parent
+    let summaryLevel = {
+      parent: topicObject,
+      indent: indent + 4, // Reserve indentation level for subtopics
+      boundaries: [],
+      summaries: []
+    }
+
+    // Add new level or replace existing level with same indentation
+    const existingLevelIndex = status.levels.findIndex(l => l.indent === indent + 4)
+    if (existingLevelIndex >= 0) {
+      status.levels[existingLevelIndex] = summaryLevel
+    } else {
+      status.levels.push(summaryLevel)
+    }
+
     return
   }
 
@@ -106,7 +123,7 @@ function addLine(line: string, status: any) {
       topicObject.title = line
 
       parentObject.boundaries
-        .filter(b => b.name == name)
+        ?.filter(b => b.name == name)
         .some(b => {
           let index = parentObject.children.attached.indexOf(topicObject)
 
@@ -133,7 +150,7 @@ function addLine(line: string, status: any) {
       topicObject.title = line
 
       parentObject.summaries
-        .filter(b => b.name == name)
+        ?.filter(b => b.name == name)
         .some(b => {
           let index = parentObject.children.attached.indexOf(topicObject)
 
diff --git a/src/parser/relstionship.spec.ts b/src/parser/relationship.spec.ts
similarity index 100%
rename from src/parser/relstionship.spec.ts
rename to src/parser/relationship.spec.ts
diff --git a/src/parser/summary.spec.ts b/src/parser/summary.spec.ts
index b49a88f..d2ab12e 100644
--- a/src/parser/summary.spec.ts
+++ b/src/parser/summary.spec.ts
@@ -98,4 +98,56 @@ central topic
 
 
     })
+
+    it('SubSubtopics', () => {
+        let map = createMapByXMindMark(`
+central topic
+- subtopic 1[S]
+    - subsubtopic 1
+[S] summary topic
+    - summarySubtopic 1
+    - summarySubtopic 2
+        `)
+
+        let subtopic1 = map.rootTopic.children.attached[0];
+        strictEqual('subtopic 1', subtopic1.title);
+
+        // Verify subtopic 1's child topic, now there's only one child
+        strictEqual('subsubtopic 1', subtopic1.children.attached[0].title);
+
+        // Verify summary topic
+        let summaryTopic = map.rootTopic.children.summary[0];
+        strictEqual('summary topic', summaryTopic.title);
+
+        // Verify child topics under summary topic
+        strictEqual('summarySubtopic 1', summaryTopic.children.attached[0].title);
+        strictEqual('summarySubtopic 2', summaryTopic.children.attached[1].title);
+
+        // Verify summary relationship
+        let summary = map.rootTopic.summaries[0];
+        strictEqual('(0,0)', summary.range);
+        strictEqual(summaryTopic.id, summary.topicId);
+    })
+
+    it('Subtopics with boundaries', () => {
+        let map = createMapByXMindMark(`
+central topic
+* topic 1 [S]
+* topic 2 [S]
+[S] summary topic
+    - subtopic 1 [B]
+    - subtopic 2 [B]
+    [B] boundary topic
+    `)
+        let summaryTopic = map.rootTopic.children.summary[0]
+        strictEqual('summary topic', summaryTopic.title)
+        strictEqual('subtopic 1 ', summaryTopic.children.attached[0].title)
+        strictEqual('subtopic 2 ', summaryTopic.children.attached[1].title)
+        let summary = map.rootTopic.summaries[0]
+        strictEqual('(0,1)', summary.range)
+        strictEqual(summaryTopic.id, summary.topicId)
+        let boundary = summaryTopic.boundaries[0]
+        strictEqual('(0,1)', boundary.range)
+        strictEqual('boundary topic', boundary.title)
+    })
 })