diff --git a/lib/download.js b/lib/download.js
index fe1abc1..eb1d89a 100644
--- a/lib/download.js
+++ b/lib/download.js
@@ -3,7 +3,6 @@ const path = require("path");
 const fs = require("mz/fs");
 const mkdirp = require("mkdirp-then");
 const request = require("requisition");
-const zfill = require("zfill");
 const { JSDOM } = require("jsdom");
 
 const FILENAME_PREFIX = "chapter";
@@ -39,7 +38,7 @@ async function downloadAllChapters(manifest, startChapterURL, cachePath, manifes
   await mkdirp(cachePath);
 
   while (currentChapter !== null) {
-    const filename = `${FILENAME_PREFIX}${zfill(chapterIndex, 3)}.html`;
+    const filename = `${FILENAME_PREFIX}${chapterIndex.toString().padStart(3, "0")}.html`;
 
     console.log(`Downloading ${currentChapter}`);
 
diff --git a/npm-shrinkwrap.json b/npm-shrinkwrap.json
index c2d67bf..aab91db 100644
--- a/npm-shrinkwrap.json
+++ b/npm-shrinkwrap.json
@@ -2114,11 +2114,6 @@
         "decamelize": "^1.2.0"
       }
     },
-    "zfill": {
-      "version": "0.0.2",
-      "resolved": "https://registry.npmjs.org/zfill/-/zfill-0.0.2.tgz",
-      "integrity": "sha1-tzfH9xhK13hMd4QNkgMczor3eUQ="
-    },
     "zip-stream": {
       "version": "2.1.2",
       "resolved": "https://registry.npmjs.org/zip-stream/-/zip-stream-2.1.2.tgz",
diff --git a/package.json b/package.json
index dd70a64..69aa258 100644
--- a/package.json
+++ b/package.json
@@ -29,8 +29,7 @@
     "thenify": "^3.3.0",
     "throat": "^5.0.0",
     "xmlserializer": "^0.6.1",
-    "yargs": "^13.3.0",
-    "zfill": "0.0.2"
+    "yargs": "^13.3.0"
   },
   "devDependencies": {
     "eslint": "6.1.0"