diff --git a/lib/scripto.js b/lib/scripto.js
index d4a973a..97bc60b 100644
--- a/lib/scripto.js
+++ b/lib/scripto.js
@@ -29,10 +29,27 @@ function Scripto (redisClient) {
 
     this.run = function run(scriptName, keys, args, callback) {
 
-        if(scripts[scriptName]) {  
+        if(scripts[scriptName]) {
             if(scriptShas[scriptName]) {
                 var sha = scriptShas[scriptName];
-                evalShaScript(redisClient, sha, keys, args, callback);
+                evalShaScript(redisClient, sha, keys, args, function(err, result) {
+                    if(err && isScriptNotLoadedError(err)) {
+                        /**
+                         * The script was once loaded but is no longer loaded.
+                         * We may have switched redis instances using sentinel
+                         */
+                        loadScriptIntoRedis(redisClient, scripts[scriptName], function(err, sha) {
+                            if(err) return callback(err);
+
+                            scriptShas[scriptName] = sha;
+                            evalShaScript(redisClient, sha, keys, args, callback);
+                        });
+
+                        return;
+                    }
+
+                    callback(err, result);
+                });
             } else {
                 var script = scripts[scriptName];
                 evalScript(redisClient, script, keys, args, callback);
@@ -125,7 +142,7 @@ function loadScriptsIntoRedis (redisClient, scripts, callback) {
         if(cnt < keys.length) {
             var key = keys[cnt++];
 
-            redisClient.send_command('script', ['load', scripts[key]], function(err, sha) {
+            loadScriptIntoRedis(redisClient, scripts[key], function(err, sha) {
 
                 if(err) {
                     callback(err);
@@ -141,6 +158,14 @@ function loadScriptsIntoRedis (redisClient, scripts, callback) {
     })();
 }
 
+function isScriptNotLoadedError(err) {
+    return err.message && err.message.indexOf('NOSCRIPT No matching script') === 0;
+}
+
+function loadScriptIntoRedis(redisClient, script, callback) {
+    redisClient.send_command('script', ['load', script], callback);
+}
+
 function evalScript(redisClient, script, keys, args, callback) {
 
     var keysLength= keys.length || 0;
diff --git a/test/scripto.js b/test/scripto.js
index 9efde23..6ab3608 100644
--- a/test/scripto.js
+++ b/test/scripto.js
@@ -130,6 +130,21 @@ suite('Scripto', function() {
 
     }));
 
+    test('reload a script if its no longer in the script cache', _clean(function(done) {
+
+        var s = new Scripto(redisClient);
+        s.loadFromFile('read-write', path.resolve(scriptDir, 'read-write.lua'));
+        redisClient.script('flush', function() {
+            s.run('read-write', ['helloKey'], [200], function(err, result) {
+
+                assert.equal(err, null);
+                assert.equal(result, 200);
+                done();
+            });
+        });
+
+    }));
+
 });
 
 function _clean(callback) {