diff --git a/beacon-chain/params/config.go b/beacon-chain/params/config.go
index 4a116054b..4fa7a0085 100644
--- a/beacon-chain/params/config.go
+++ b/beacon-chain/params/config.go
@@ -44,7 +44,7 @@ var defaultConfig = &Config{
 }
 
 var demoConfig = &Config{
-	GenesisTime:        time.Now(),
+	GenesisTime:        time.Now().Add(-8 * time.Second),
 	CycleLength:        uint64(5),
 	ShardCount:         3,
 	DefaultBalance:     new(big.Int).Div(big.NewInt(32), big.NewInt(int64(1e18))),
diff --git a/beacon-chain/simulator/service.go b/beacon-chain/simulator/service.go
index 2f214310b..597404ca8 100644
--- a/beacon-chain/simulator/service.go
+++ b/beacon-chain/simulator/service.go
@@ -182,7 +182,7 @@ func (sim *Simulator) run(delayChan <-chan time.Time, done <-chan struct{}) {
 			}
 
 			block := types.NewBlock(&pb.BeaconBlock{
-				SlotNumber:            sim.slotNum,
+				SlotNumber:            sim.chainService.CurrentBeaconSlot(),
 				Timestamp:             ptypes.TimestampNow(),
 				PowChainRef:           powChainRef,
 				ActiveStateHash:       activeStateHash[:],
diff --git a/beacon-chain/simulator/service_test.go b/beacon-chain/simulator/service_test.go
index 7642f7b6e..fb24c102f 100644
--- a/beacon-chain/simulator/service_test.go
+++ b/beacon-chain/simulator/service_test.go
@@ -55,6 +55,10 @@ func (mc *mockChainService) GenesisBlock() (*types.Block, error) {
 	return types.NewGenesisBlock([32]byte{}, [32]byte{}), nil
 }
 
+func (mc *mockChainService) CurrentBeaconSlot() uint64 {
+	return 0
+}
+
 func TestLifecycle(t *testing.T) {
 	hook := logTest.NewGlobal()
 	db := database.NewKVStore()
diff --git a/beacon-chain/types/interfaces.go b/beacon-chain/types/interfaces.go
index 67db234f7..9ab5fa9bd 100644
--- a/beacon-chain/types/interfaces.go
+++ b/beacon-chain/types/interfaces.go
@@ -52,6 +52,7 @@ type StateFetcher interface {
 	CurrentActiveState() *ActiveState
 	CurrentCrystallizedState() *CrystallizedState
 	GenesisBlock() (*Block, error)
+	CurrentBeaconSlot() uint64
 }
 
 // POWChainService is an interface for a proof-of-work chain web3 service.