diff --git a/untitled/content.py b/untitled/content.py
index 5a408b2..76a1186 100644
--- a/untitled/content.py
+++ b/untitled/content.py
@@ -4,6 +4,7 @@ GAME_NAME = "Untitled Cat Game"  # Titled Cat Game
 SAVE_VERSION = 2
 
 HUNGER_DECAY_PER_HOUR = 5
+BASE_HAPPINESS_DECAY_PER_HOUR = 5
 
 CAT_COLORS = [
     "orange tabby",
diff --git a/untitled/model.py b/untitled/model.py
index 6180029..d349376 100644
--- a/untitled/model.py
+++ b/untitled/model.py
@@ -2,10 +2,11 @@ import time
 
 
 class Cat:
-    def __init__(self, name, traits, fullness=100, last_updated=None):
+    def __init__(self, name, traits, fullness=100, happiness=100, last_updated=None):
         self.name = name
         self.traits = traits
         self.fullness = fullness
+        self.happiness = happiness
         self.last_updated = last_updated if last_updated is not None else time.time()
 
     def to_dict(self):
@@ -13,12 +14,19 @@ class Cat:
             "name": self.name,
             "traits": self.traits,
             "fullness": self.fullness,
+            "happiness": self.happiness,
             "last_updated": self.last_updated,
         }
 
     @staticmethod
     def from_dict(data):
-        return Cat(data["name"], data["traits"], data["fullness"], data["last_updated"])
+        return Cat(
+            data["name"],
+            data["traits"],
+            data["fullness"],
+            data["happiness"],
+            data["last_updated"],
+        )
 
 
 class Save:
diff --git a/untitled/rules.py b/untitled/rules.py
index fbb97bd..bb8d7dd 100644
--- a/untitled/rules.py
+++ b/untitled/rules.py
@@ -1,6 +1,6 @@
 import string
 
-from untitled import content
+from untitled import content, model
 
 
 def validate_cat_name(name, auto_gen=False):
@@ -17,13 +17,16 @@ def validate_cat_name(name, auto_gen=False):
         return "Your cat's name needs at least 1 letter."
 
 
-def reconcile(cat, now):
+def reconcile(cat: model.Cat, now):
     elapsed_hours = (now - cat.last_updated) / 3600
     if elapsed_hours <= 0:
         return
     cat.fullness -= content.HUNGER_DECAY_PER_HOUR * elapsed_hours
     if cat.fullness < 0:
         cat.fullness = 0
+    cat.happiness -= content.BASE_HAPPINESS_DECAY_PER_HOUR * elapsed_hours
+    if cat.happiness < 0:
+        cat.happiness = 0
     cat.last_updated = now