diff --git a/roman-time.js b/roman-time.js
index f66353e..6b9c63d 100644
--- a/roman-time.js
+++ b/roman-time.js
@@ -5,8 +5,40 @@
  * @returns {String} – время римскими цифрами (IX:V)
  */
 function romanTime(time) {
-    // Немного авторского кода и замечательной магии
-    return time;
+    var tokens = time.split(':');
+
+    var hours = parseInt(tokens[0], 10);
+    var minutes = parseInt(tokens[1], 10);
+
+    if (checkHours(hours) || checkMinutes(minutes)) {
+        throw new TypeError('Неверное время');
+    }
+
+    return toRoman(hours) + ':' + toRoman(minutes);
+}
+
+function checkHours(hours) {
+    return isNaN(hours) || hours < 0 || hours > 23;
+}
+
+function checkMinutes(minutes) {
+    return isNaN(minutes) || minutes < 0 || minutes > 60;
+}
+
+function toRoman(number) {
+    var ones = ['', 'I', 'II', 'III', 'IV', 'V', 'VI', 'VII', 'VIII', 'IX'];
+    var tens = ['', 'X', 'XX', 'XXX', 'XL', 'L', 'LX', 'LXX', 'LXXX'];
+    var zero = 'N';
+
+    var result = '';
+    result += ones[number % 10];
+    result += tens[Math.floor(number / 10) % 10];
+
+    if (result === '') {
+        result = zero;
+    }
+
+    return result;
 }
 
 module.exports = romanTime;